Jefferson River
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The Jefferson River is a
tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainage ...
of the Missouri River, approximately long, in the
U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sover ...
of
Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...
. The Jefferson River and the
Madison River The Madison River is a headwater tributary of the Missouri River, approximately 183 miles (295 km) long, in Wyoming and Montana. Its confluence with the Jefferson and Gallatin rivers near Three Forks, Montana forms the Missouri River. The ...
form the official beginning of the Missouri at Missouri Headwaters State Park near Three Forks. It is joined downstream (northeast) by the Gallatin. From broad valleys to a narrow canyon, the Jefferson River passes through a region of significant geological diversity, with some of the oldest and youngest rocks of North America and a diversity of igneous, metamorphic, and sedimentary formations. The region was only intermittently inhabited by Native Americans until relatively recent times, and no single tribe had exclusive use of the Jefferson River when the Lewis and Clark Expedition first ascended the river in 1805. Today, the Jefferson River retains much of its scenic beauty and wildlife diversity from the days of Lewis and Clark, yet is threatened by water use issues and encroaching development. The Jefferson is a segment of the
Lewis and Clark National Historic Trail The Lewis and Clark National Historic Trail is a route across the United States commemorating the Lewis and Clark Expedition of 1804 to 1806. It is part of the National Trails System of the United States. It extends for some from Pittsburgh, Pe ...
, administered by the
National Park Service The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational propertie ...
.


Course

From the
Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...
of southwestern
Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...
, three small rivers converge to form the headwaters of the Jefferson River. The longest begins at
Brower's Spring Brower's Spring is a spring in the Centennial Mountains of Beaverhead County, Montana that was marked by a surveyor in 1888 as the ultimate headwaters of the Missouri River and thus the fourth longest river in the world, the Mississippi-Missour ...
, 9,030 feet (2,750 m) above sea level, on the northern flank of the
Centennial Mountains The Centennial Mountains are the southernmost sub-range of the Bitterroot Range in the U.S. states of Idaho and Montana. The Centennial Mountains include the Western and Eastern Centennial Mountains. The range extends east from Monida Pass along ...
. The site is marked by a pile of rocks. The water flows west then north as
Hell Roaring Creek Hell Roaring Creek is a fast-running creek in southern Montana. The creek flows from Brower's Spring, which is considered the ultimate source of the Missouri River.Demetriades , Anthony (July/August 2005"The True Utmost Reaches of the Missouri ...
before merging with Rock Creek and flowing west through Upper and Lower Red Rock Lakes. Here it becomes the Red Rock River, flowing west through Lima Reservoir and then northwest into Clark Canyon Reservoir near
Dillon Dillon may refer to: People *Dillon (surname) * Dillon (given name) * Dillon (singer) (born 1988), Brazilian singer *Viscount Dillon, a title in the Peerage of Ireland Places Canada *Dillon, Saskatchewan United States *Dillon Beach, Californi ...
. Below the dam, the river is known as the
Beaverhead River The Beaverhead River is an approximately tributary of the Jefferson River in southwest Montana (east of the Continental Divide). It drains an area of roughly . The river's original headwaters, formed by the confluence of the Red Rock River and ...
. It is joined by the
Ruby River The Ruby River is a tributary of the Beaverhead River, approximately 76 mi (122 km) long, in southwestern Montana in the United States. It rises in the Beaverhead National Forest in southwestern Madison County between the Snowcrest ...
above the town of Twin Bridges and converges with the
Big Hole River The Big Hole River is a tributary of the Jefferson River, approximately long, in Beaverhead County, in southwestern Montana, United States. It is the last habitat in the contiguous United States for native fluvial Arctic grayling and is a h ...
to form the Jefferson about two miles downstream from town. The Jefferson River flows north through the Jefferson Valley towards
Whitehall Whitehall is a road and area in the City of Westminster, Central London. The road forms the first part of the A roads in Zone 3 of the Great Britain numbering scheme, A3212 road from Trafalgar Square to Chelsea, London, Chelsea. It is the main ...
and then east, where it is joined by the Boulder River before passing through the narrow Jefferson River canyon near
Lewis and Clark Caverns State Park Lewis and Clark Caverns State Park is a public recreation and nature preservation area located east of Whitehall in Jefferson County, Montana. The state park includes two visitor centers, ten miles of hiking trails, a campground, and its names ...
. After the canyon, the river passes into a broad valley again near Willow Creek. The Jefferson converges with the
Madison River The Madison River is a headwater tributary of the Missouri River, approximately 183 miles (295 km) long, in Wyoming and Montana. Its confluence with the Jefferson and Gallatin rivers near Three Forks, Montana forms the Missouri River. The ...
at Missouri Headwaters State Park near Three Forks to form the Missouri River, joined a short distance downstream by the
Gallatin River The Gallatin River is a tributary of the Missouri River, approximately 120 mi (193 km long), in the U.S. states of Wyoming and Montana. It is one of three rivers, along with the Jefferson River, Jefferson and Madison River, Madison, ...
. After flowing into the Missouri, its waters continue into the
Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it f ...
, eventually into the
Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...
. These rivers combine to be the fourth longest river on Earth.


Geology

The geology of the Jefferson River and the surrounding mountain ranges includes some of the oldest rocks found in North America, dating back to the
Archean The Archean Eon ( , also spelled Archaean or Archæan) is the second of four geologic eons of Earth's history, representing the time from . The Archean was preceded by the Hadean Eon and followed by the Proterozoic. The Earth Earth ...
Eon, 2.7 billion years ago.Montana Geology ’05 Calendar. Montana Bureau of Mines and Geology. Butte, Montana. 2005. Found primarily in the Tobacco Root and
Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sa ...
ranges, these ancient rocks are
metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causin ...
, having been highly compressed and nearly re-melted by geologic forces over eons of time. Frequently found along the Jefferson River, these rocks include layered feldspars, gneiss, glassy quartz, heavy dark amphibolite, and sometimes marble.Ruby Valley Geology. http://www.sheridanwired.com/index.php/visitor-info/66/74-ruby-valley-geology . About a billion years ago, the Willow Creek Fault, north of the Jefferson River canyon, dropped down deeply and filled with seawater, stretching north to Alberta and British Columbia. Eventually, the sea receded and erosion wore away intervening geologic history until about 530 million years ago, during the
Cambrian Period The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...
of the
Paleozoic Era The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...
. A new sea encroached on the land, depositing
sedimentary Sedimentary rocks are types of rock (geology), rock that are formed by the accumulation or deposition of mineral or organic matter, organic particles at Earth#Surface, Earth's surface, followed by cementation (geology), cementation. Sedimentati ...
layers of
limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
,
dolomite Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincor ...
,
shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...
, and
sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...
over several hundred million years. Limestone is generally made of calcium from marine animals that have been compacted and cemented together. Dolomite is similar but has more magnesium. Shale is formed from fine-grained mud, silts, and clays that have been compacted and cemented together. The sandstone is made up of quartz and feldspar. By the Mississippian Period, 340 million years ago, much of western North America was covered with a warm, shallow sea, much like the Gulf Coast of Florida today. Small marine fossils can be found in the
Madison Group The Madison Limestone is a thick sequence of mostly carbonate rocks of Mississippian age in the Rocky Mountain and Great Plains areas of the western United States. The rocks serve as an important aquifer as well as an oil reservoir in places. Th ...
limestone that makes up the steep, narrow section of the Jefferson River canyon today. Gentle uplift eventually raised the region above sea level again. Rainwater percolated down through cracks in the limestone, dissolving rock and creating caves such as those found at
Lewis and Clark Caverns State Park Lewis and Clark Caverns State Park is a public recreation and nature preservation area located east of Whitehall in Jefferson County, Montana. The state park includes two visitor centers, ten miles of hiking trails, a campground, and its names ...
. Local mountains, such as the Tobacco Roots were formed from the
Boulder Batholith The Boulder Batholith is a relatively small batholith in southwestern Montana, United States, exposed at the surface as granite (more specifically quartz monzonite) and serving as the host rock for rich mineralized deposits at Butte and other loc ...
. The batholith is composed of at least seven, and possibly as many as fourteen, discrete
igneous Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or ...
rock masses called
plutons In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...
, which formed beneath the Earth’s surface during a period of
magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...
intrusion In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...
about 73 to 78 million years ago during the
Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...
. The rising buoyant plutons resulted from
subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...
along what was then the west coast of North America. Regional uplift brought the deep-seated
granite Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...
to the surface, where erosion exposed the rocks and the mineral veins they contained. The granite generally consists of quartz, hornblende, and feldspars. Gold, silver, and other semi precious minerals are also associated with batholiths. The ancient metamorphic and more recent sedimentary layers above the batholiths eroded away as the magma pushed up through the crust. Thus, the granite batholiths are typically found at the center of local mountain ranges, while the much older metamorphic gneiss is usually found lower in the mountains, and limestone layers are mostly found in the foothills nearest the Jefferson River. The Rocky Mountains began a new and continuing phase of crustal stress 5 to 10 million years ago as tectonic forces began to pull the region apart. Blocks of earth dropped down to form valleys, and the Jefferson River eroded a channel through rock to form the Jefferson River canyon.


First peoples

Archaeologists believe that the first Americans migrated across the Bering land bridge from Asia between 12,000 and 30,000 years ago. They followed the Great North Trail, which dipped down into Montana along the east slope of the Rocky Mountains. These Paleo-Indians or Clovis people hunted the now-extinct mammoths and bison with Clovis points. Clovis points dated 12,000 to 13,000 years old have been found along the Missouri River near
Townsend Townsend (pronounced tounʹ-zənd) or Townshend may refer to: Places United States *Camp Townsend, National Guard training base in Peekskill, New York *Townsend, Delaware *Townsend, Georgia *Townsend, Massachusetts, a New England town ** Townsend ...
, Montana, about forty-five miles beyond the Jefferson.Bryan, William L., Jr. Montana Indians: Yesterday and Today, 2nd Edition. American & World Geographic Publishing: Helena, MT. 1996, p. 6. Paleo-Indians seldom entered the Rockies, where glaciation persisted. Upstream from the Jefferson, at
Barton Gulch Barton Gulch is an archaeological site in southwest Montana that has provided very important information concerning some of the earliest residents of the Paleo-Indian period in the northwest United States. Geography The Barton Gulch site is loc ...
, a tributary of the
Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sa ...
-Jefferson River system, archaeologists excavated an extensive complex of Paleo-Indian cooking pits and earth ovens dated to 9400
RCYBP Before Present (BP) years, or "years before present", is a geologic time scale, time scale used mainly in archaeology, geology and other science, scientific disciplines to specify when events occurred relative to the origin of practical radiocarbo ...
. Between 6,000 and 7,000 years ago, climate change brought dramatically drier conditions to the Northern Rockies. It is thought that far fewer animals survived in the region and the native peoples likely migrated elsewhere. Montana was apparently only intermittently inhabited after that until relatively recent times. In the 1500s, the
Kootenai The Kutenai ( ), also known as the Ktunaxa ( ; ), Ksanka ( ), Kootenay (in Canada) and Kootenai (in the United States), are an indigenous people of Canada and the United States. Kutenai bands live in southeastern British Columbia, northern ...
came into Montana from the north. The
Salish Salish () may refer to: * Salish peoples, a group of First Nations/Native Americans ** Coast Salish peoples, several First Nations/Native American groups in the coastal regions of the Pacific Northwest ** Interior Salish peoples, several First Nat ...
and
Pend d'Oreille The Pend d'Oreille ( ), also known as the Kalispel (), are Indigenous peoples of the Northwest Plateau. Today many of them live in Montana and eastern Washington of the United States. The Kalispel peoples referred to their primary tribal range a ...
migrated in from the north and northwest, venturing south to the Jefferson River/Missouri Headwaters and eastward. Major population shifts started in the early 1600s, bringing several new tribes into Montana. With horses of Spanish origin, the
Shoshone The Shoshone or Shoshoni ( or ) are a Native American tribe with four large cultural/linguistic divisions: * Eastern Shoshone: Wyoming * Northern Shoshone: southern Idaho * Western Shoshone: Nevada, northern Utah * Goshute: western Utah, easter ...
migrated into Montana from the
Great Basin The Great Basin is the largest area of contiguous endorheic basin, endorheic watersheds, those with no outlets, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja California ...
and hunted buffalo, becoming the dominant tribe in the area. However, the arrival and expansion of European settlers on the east coast pushed Native Americans west, in a domino effect that extended all the way into Montana. The
Crow A crow is a bird of the genus '' Corvus'', or more broadly a synonym for all of ''Corvus''. Crows are generally black in colour. The word "crow" is used as part of the common name of many species. The related term "raven" is not pinned scientifica ...
migrated into Montana from the east in the 1600s, followed by the
Blackfeet The Blackfeet Nation ( bla, Aamsskáápipikani, script=Latn, ), officially named the Blackfeet Tribe of the Blackfeet Indian Reservation of Montana, is a federally recognized tribe of Siksikaitsitapi people with an Indian reservation in Monta ...
,
Gros Ventre The Gros Ventre ( , ; meaning "big belly"), also known as the Aaniiih, A'aninin, Haaninin, Atsina, and White Clay, are a historically Algonquian-speaking Native American tribe located in north central Montana. Today the Gros Ventre people are ...
, and
Assiniboine The Assiniboine or Assiniboin people ( when singular, Assiniboines / Assiniboins when plural; Ojibwe: ''Asiniibwaan'', "stone Sioux"; also in plural Assiniboine or Assiniboin), also known as the Hohe and known by the endonym Nakota (or Nakoda ...
in the 1700s. With the acquisition of guns and horses, the Blackfeet became the dominant tribe on the plains in the 1700s. The Shoshone were largely pushed back over the continental divide into Idaho, but still ventured into Montana hunting and foraging. By 1800, the Missouri headwaters and much of southwest Montana was a crossroads frequented by the
Lemhi Shoshone The Lemhi Shoshone are a tribe of Northern Shoshone, also called the Akaitikka, Agaidika, or "Eaters of Salmon".Murphy and Murphy, 306 The name "Lemhi" comes from Fort Lemhi, a Mormon mission to this group. They traditionally lived in the Lemhi Ri ...
,
Bannock Bannock may mean: * Bannock (food), a kind of bread, cooked on a stone or griddle * Bannock (Indigenous American), various types of bread, usually prepared by pan-frying * Bannock people, a Native American people of what is now southeastern Oregon ...
,
Nez Perce The Nez Percé (; autonym in Nez Perce language: , meaning "we, the people") are an Indigenous people of the Plateau who are presumed to have lived on the Columbia River Plateau in the Pacific Northwest region for at least 11,500 years.Ames, K ...
, Flathead,
Crow A crow is a bird of the genus '' Corvus'', or more broadly a synonym for all of ''Corvus''. Crows are generally black in colour. The word "crow" is used as part of the common name of many species. The related term "raven" is not pinned scientifica ...
,
Sioux The Sioux or Oceti Sakowin (; Dakota language, Dakota: Help:IPA, /otʃʰeːtʰi ʃakoːwĩ/) are groups of Native Americans in the United States, Native American tribes and First Nations in Canada, First Nations peoples in North America. The ...
, and
Piegan Blackfeet The Piegan ( Blackfoot: ''Piikáni'') are an Algonquian-speaking people from the North American Great Plains. They were the largest of three Blackfoot-speaking groups that made up the Blackfoot Confederacy; the Siksika and Kainai were the oth ...
.
Sacagawea Sacagawea ( or ; also spelled Sakakawea or Sacajawea; May – December 20, 1812 or April 9, 1884)Sacagawea
...
, of the Lemhi Shoshone, was captured by the
Hidatsa The Hidatsa are a Siouan people. They are enrolled in the federally recognized Three Affiliated Tribes of the Fort Berthold Reservation in North Dakota. Their language is related to that of the Crow, and they are sometimes considered a parent t ...
on the lower Jefferson River in 1800, when she was about twelve years old. She was later married to
Toussaint Charbonneau Toussaint Charbonneau (March 20, 1767 – August 12, 1843) was a French-Canadian explorer, trader and a member of the Lewis and Clark Expedition. He is also known as the husband of Sacagawea. Early years Charbonneau was born in Boucherv ...
and both of them joined the
Lewis and Clark Expedition The Lewis and Clark Expedition, also known as the Corps of Discovery Expedition, was the United States expedition to cross the newly acquired western portion of the country after the Louisiana Purchase. The Corps of Discovery was a select gro ...
when Lewis and Clark wintered with the Hidatsa in North Dakota in 1804-05.


Lewis and Clark Expedition

Little was known about the American West at the beginning of the nineteenth century. The Missouri River flowed southeast from an unknown source, joining the Mississippi River before flowing south to the Gulf of Mexico. The Columbia River originated at a similar latitude as the Missouri, and flowed west to the Pacific Ocean. What lay in between was the subject of much speculation. The United States acquired the Missouri River watershed through the
Louisiana Purchase The Louisiana Purchase (french: Vente de la Louisiane, translation=Sale of Louisiana) was the acquisition of the territory of Louisiana by the United States from the French First Republic in 1803. In return for fifteen million dollars, or app ...
of 1803, and President
Thomas Jefferson Thomas Jefferson (April 13, 1743 – July 4, 1826) was an American statesman, diplomat, lawyer, architect, philosopher, and Founding Fathers of the United States, Founding Father who served as the third president of the United States from 18 ...
sent
Meriwether Lewis Meriwether Lewis (August 18, 1774 – October 11, 1809) was an American explorer, soldier, politician, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition, also known as the Corps of Discovery, with ...
and
William Clark William Clark (August 1, 1770 – September 1, 1838) was an American explorer, soldier, Indian agent, and territorial governor. A native of Virginia, he grew up in pre-statehood Kentucky before later settling in what became the state of Misso ...
with a company of men to explore up the Missouri in the hopes of finding a navigable water route to the Pacific, with a low portage connecting one watershed with the other. The Expedition departed from Saint Louis, Missouri in the spring of 1804, ascended the Missouri River that summer, then wintered over with the Hidatsa Indians in North Dakota, where they met Toussaint Charbonneau and his Shoshone wife Sacagawea. Lewis and Clark hired Charbonneau to join the expedition, in part because Sacagawea's people were native to the Missouri headwaters. The Lewis and Clark Expedition arrived at the Missouri Headwaters on 27 July 1805. Of the three streams that make up the headwaters of the Missouri, the eastern fork is the smallest, while the larger middle and western forks are of relatively equal size. Therefore, Lewis and Clark concluded that it would be inappropriate for any fork to retain the name "Missouri." Instead, they named the western fork the Jefferson, the middle fork as the Madison, and the eastern fork as the Gallatin, as
Meriwether Lewis Meriwether Lewis (August 18, 1774 – October 11, 1809) was an American explorer, soldier, politician, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition, also known as the Corps of Discovery, with ...
noted in his journal on July 28, 1805: :''"Both Capt. C. and myself in opinion with to the impropriety of calling either of these '' hree' streams the Missouri and accordingly agreed to name them after the
President of the United States The president of the United States (POTUS) is the head of state and head of government of the United States of America. The president directs the executive branch of the federal government and is the commander-in-chief of the United Stat ...
and the Secretaries of the
Treasury A treasury is either *A government department related to finance and taxation, a finance ministry. *A place or location where treasure, such as currency or precious items are kept. These can be state or royal property, church treasure or in p ...
and
state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * ''The State'' (newspaper), a daily newspaper in Columbia, South Carolina, United States * ''Our S ...
..."'' The expedition rested a couple days at the Missouri headwaters, then began to ascend the Jefferson River, using ropes to pull the dugout canoes upstream against the current. Along the way they hunted deer, elk, bighorn sheep, and encountered grizzly bears. Describing the upper Jefferson River, Lewis recorded on August 2, 1805:
The valley though which our rout of this aylay and through which the river winds it's meandering course is a beatifull level plain with but little timber and that on the verge of the river. the land is tolerably fertile, consisting of a black or dark yellow loam, and covered with grass from 9 Inches to 2 feet high. The plain ascends gradually on either side of the river to the bases of two ranges of mountains which ly parallel to the river and which terminate 〈it's〉 the width of the vally. the tops of these mountains were yet partially covered with snow while we in the valley. were suffocated nearly with the intense heat of the midday sun. the nights are so could that two blankets are not more than sufficient covering.
Arriving at a major confluence, Lewis and Clark named the western fork the Wisdom River, the eastern fork the Philanthropy River and retained the middle fork as a continuation of the Jefferson River. However, none of these names were retained. These rivers are known today as the
Big Hole The Kimberley Mine or Tim Kuilmine ( af, Groot Gat) is an open-pit and underground mine in Kimberley, South Africa, and claimed to be the deepest hole excavated by hand, although this claim is disputed. History and size The first diamonds he ...
, the
Ruby A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sa ...
, and the Beaverhead. The Jefferson River is a segment of the
Lewis and Clark National Historic Trail The Lewis and Clark National Historic Trail is a route across the United States commemorating the Lewis and Clark Expedition of 1804 to 1806. It is part of the National Trails System of the United States. It extends for some from Pittsburgh, Pe ...
, established by Congress in 1978 and administered by the
National Park Service The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational propertie ...
.


Recreation

The Jefferson River is rated as Class I water for recreational purposes from its origin at the Beaverhead and Big Hole rivers to its confluence with the Missouri at Three Forks. The river is suitable for floaters and beginning paddlers, except during high water flows in the spring. Possible hazards include downed trees, called "sweeps" and diversion dams constructed to channel river water into irrigation ditches. Water levels often drop off by mid-summer, making it necessary to drag watercraft over shallow riffles. The Jefferson River consists of three distinct sections. The upper Jefferson is a much-braided, meandering river and floodplain system that supports productive farm fields, extensive cottonwood groves, rich meadows, and abundant wildlife. The river creates diverse habitats as it naturally shifts back and forth across the Jefferson Valley, forming oxbows and swamps of various depth and age. Shifting channels and natural flooding facilitates the germination of cottonwood seedlings. Individual cottonwood groves are often germinated from a single flood event and tend to be of uniform age. The upper Jefferson extends from the confluence of the
Big Hole The Kimberley Mine or Tim Kuilmine ( af, Groot Gat) is an open-pit and underground mine in Kimberley, South Africa, and claimed to be the deepest hole excavated by hand, although this claim is disputed. History and size The first diamonds he ...
and the Beaverhead rivers approximately 44 miles downstream to the community of Cardwell. The middle Jefferson enters a narrow canyon a short distance downstream from Cardwell and is largely contained by the geography for most of the next 15 miles downstream to Sappington Bridge. Lacking the ability to flood or meander, this section of the river has few trees, swamps, meadows, and significantly less wildlife than the upper Jefferson. The lower Jefferson opens up again into a meandering, braided river from Sappington bridge approximately 24 miles downstream to its confluence with the Madison River. Here, the riparian zone again supports an extensive community of swamps, meadows, cottonwood groves, and productive farm lands.


Environmental Degradation

Throughout its length, the Jefferson River is used extensively as a source of irrigation water for local farms and ranches. Dams constructed upstream on the Ruby and Beaverhead rivers store surplus water from spring runoff which is released to augment natural flows during the summer irrigation season. However, portions of the river can become severely dewatered, shallow, and warm in drought years, adversely impacting fish populations. The unnaturally warm water, combined with excess nutrients from irrigation runoff and grazing practices, can stimulate rapid growth of algae in mid-summer, to the detriment of anglers and floaters. On August 5, 2016 the Jefferson River stream flow was measured at only 19 CFS (cubic feet per second). This occurred even while the three main tributaries to the Jefferson were contributing 1140 CFS. The Ruby River was measured at 310 CFS, the Big Hole River was measured at 200 CFS and the Beaverhead River was measured at 630 CFS. Irrigators took over 98% of this stream flow by forcing the river into irrigation channels using diversion dams, leaving less than 2% of water in the river. Montana has no minimum stream flow legislation to prevent the total dewatering of the Jefferson River in the future. While much of the Jefferson River remains untouched and scenic, it is threatened by new
housing developments A housing estate (or sometimes housing complex or housing development) is a group of homes and other buildings built together as a single development. The exact form may vary from country to country. Popular throughout the United States ...
that incrementally fragment wildlife habitat and vistas along the river. Efforts to stabilize portions of the riverbank with rock, concrete, and other rip-rap materials have inhibited the river's ability to flood, meander, and form new cottonwood groves and wildlife habitat. In addition, rip-rapped sections of the river tend to funnel floodwaters downstream, increasing the impact to other landowners."Thinking of Building a House?" Jefferson River Canoe Trail Maps, Map 2 - Middle Jefferson River.


See also

*
Montana Stream Access Law The Montana Stream Access Law says that anglers, floaters and other recreationists in Montana have full use of most natural waterways between the high-water marks for fishing and floating, along with swimming and other river or stream-related act ...
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List of rivers of Montana The following is a partial list of rivers of Montana (U.S. state). East of Continental Divide Water in these rivers flows east and south from the Continental Divide of the Americas, also known as the Great Divide, into the Gulf of Mexico via t ...


References

{{authority control Rivers of Montana Tributaries of the Missouri River Rivers of Gallatin County, Montana