U.S. Route 18 (US 18) is an east–west

U.S. highway The United States Numbered Highway System (often called U.S. Routes or U.S. Highways) is an integrated network of roads and highways numbered within a nationwide grid in the contiguous United States. As the designation and numbering of these h ...

in the Midwestern United States. The western terminus is in Orin, Wyoming at an interchange with

Interstate 25 Interstate 25 (I-25) is a major Interstate Highway in the western United States. It is primarily a north–south highway, serving as the main route through New Mexico, Colorado, and Wyoming. I-25 stretches from I-10 at Las Cruces, New Mexic ...

. Its eastern terminus is in downtown Milwaukee, Wisconsin. However, US 18 runs concurrent with other U.S. routes from its western terminus to

Mule Creek Junction, Wyoming Mule Creek Junction is a former community in Niobrara County, Wyoming at the junction of US 18 and US 85. Geography The Junction is located on the southwest corner of the Black Hills The Black Hills ( lkt, Ȟe Sápa; chy, Moʼȯhta-voʼhon ...

. US 18 is one of the original United States highways of 1926. The US 18 designation was originally proposed for a road in Michigan from

Grand Haven Grand Haven is a city within the U.S. state of Michigan and the county seat of Ottawa County. Grand Haven is located on the eastern shore of Lake Michigan at the mouth of the Grand River, for which it is named. As of the 2010 census, Grand H ...

east to Detroit. This roadway was eventually designated as

U.S. Route 16 U.S. Route 16 (US 16) is an east–west United States Highway between Rapid City, South Dakota and Yellowstone National Park in Wyoming. The highway's eastern terminus is at a junction with Interstate 90/U.S. Route 14 (I-90/US 14), concu ...

Route description

Wyoming

In Wyoming, US 18 runs concurrent with U.S. Route 20 from

to Lusk, where US 18 branches off to run concurrently with

U.S. Route 85 U.S. Route 85 (US 85) is a north–south United States Highway that travels in the Mountain and Northern Plains states of the United States. The southern terminus of the highway is at the Mexican border in El Paso, Texas, connecting wi ...

. At the unincorporated community of Mule Creek Junction in northeastern

Niobrara County Niobrara County is a county in the U.S. state of Wyoming. As of the 2020 United States Census, the population was 2,467, making it the least populous county in Wyoming. Its county seat is Lusk. Its eastern boundary abuts the west lines of the ...

, US 18 leaves US 85. This ten-mile (16 km) stretch from US 85 to the South Dakota border is the only segment of US 18 in Wyoming which is not co-signed with another highway. Running for nearly 100 miles, US 18 has a speed limit of 70 MPH with the exception of its ending terminus at Orin and the portion throughout Lusk.

South Dakota

U.S. 18 enters South Dakota west of Edgemont. It passes through

Hot Springs A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by circ ...

, the Pine Ridge Indian Reservation, the Rosebud Indian Reservation, Winner, and Gregory before crossing the Missouri River near Pickstown over the

Fort Randall Dam Fort Randall Dam is a earthen dam which spans the Missouri River and impounds Lake Francis Case, the 11th-largest reservoir in the U.S. The dam joins Gregory and Charles Mix counties, South Dakota a distance of 880 river miles (1,416 km) u ...

. East of the Missouri River, U.S. 18 passes through (or near) Lake Andes and Tripp before a brief concurrency with Interstate 29 near Worthing. East of I-29, U.S. 18 passes through

Canton Canton may refer to: Administrative division terminology * Canton (administrative division), territorial/administrative division in some countries, notably Switzerland * Township (Canada), known as ''canton'' in Canadian French Arts and ent ...

before crossing the Big Sioux River into Iowa. The Oyate Trail is one of the names given (in the late 1990s) to the section of US-18 traveling across South Dakota from I-29 east of Vermillion to Maverick Junction. Named in an attempt to encourage more tourism traffic through the lands of various AmerInd tribes in southern South Dakota, it passes through or near the Yankton Sioux Indian Reservation, the Rosebud Indian Reservation, and the Pine Ridge Indian Reservation, crossing the James River Valley, the Missouri River near Fort Randall Dam, portions of Pine Ridge, and the High Plains of South Dakota, connecting the urban areas of the middle Missouri River with the Black Hills. Portions of the road were known as the Grant Highway, Black Hills Sioux Trail, and as part of the Omaha, Rosebud and Black Hills Highway and the Custer Battlefield Trail. Towns along the road include Gregory, Winner, Olivet, Mission,

Martin Martin may refer to: Places * Martin City (disambiguation) * Martin County (disambiguation) * Martin Township (disambiguation) Antarctica * Martin Peninsula, Marie Byrd Land * Port Martin, Adelie Land * Point Martin, South Orkney Islands Austral ...

, Batesland, and Pine Ridge. Nearby towns and locales of interest include Rosebud (capital of the Rosebud Sioux Tribe), and Wounded Knee.

Legal definition

The South Dakota section of U.S. 18, other than the concurrency with Interstate 29, is defined at South Dakota Codified Laws § 31-4-141.

Iowa

U.S. 18 enters Iowa via a Big Sioux River crossing northeast of Beloit. It overlaps

U.S. Route 75 U.S. Route 75 is a major north–south United States Numbered Highways, U.S. Highway that extends in the central United States. The highway's northern terminus is in Noyes, Minnesota, at the Canada–United States border, Canadian border, wh ...

for a mile near

Hull Hull may refer to: Structures * Chassis, of an armored fighting vehicle * Fuselage, of an aircraft * Hull (botany), the outer covering of seeds * Hull (watercraft), the body or frame of a ship * Submarine hull Mathematics * Affine hull, in affi ...

and

U.S. Route 59 U.S. Route 59 (US 59) is a north–south United States highway (though it was signed east–west in parts of Texas). A latecomer to the U.S. numbered route system, US 59 is now a border-to-border route, part of the NAFTA Corridor Highway Sy ...

for a mile near Sanborn. It then overlaps U.S. Route 71 through Spencer. U.S. 18 passes through Emmetsburg before intersecting

U.S. Route 169 U.S. Route 169 (US 169) is a north-south U.S highway that currently runs for 966 miles (1,555 km) from the city of Virginia, Minnesota to Tulsa, Oklahoma at Memorial Drive. Route description Oklahoma US 169 is a major north–south ...

at Algona. U.S. 18 then continues east through

Garner Garner may refer to: Places United States * Garner, Arkansas * Garner, Iowa * Garner, Missouri * Garner, North Carolina Other uses * Garner (surname), a surname * Granary, a grain store * ''Tennessee v. Garner'', a United States Supreme Court cas ...

before intersecting Interstate 35 in Clear Lake. After a brief concurrency with I-35, U.S. 18 continues as a freeway bypassing Mason City to the south. At

Charles City Charles is a masculine given name predominantly found in English and French speaking countries. It is from the French form ''Charles'' of the Proto-Germanic name (in runic alphabet) or ''*karilaz'' (in Latin alphabet), whose meaning was "f ...

, U.S. 18 becomes a rural two-lane highway again, except for a brief concurrency with the

U.S. Route 63 U.S. Route 63 (US 63) is a , north–south United States Highway primarily in the Midwestern and Southern United States. The southern terminus of the route is at Interstate 20 (I-20) in Ruston, Louisiana; the northern terminus is at US ...

bypass of New Hampton. After passing through West Union, it turns northeast and joins

U.S. Route 52 U.S. Route 52 (US 52) is a major United States highway in the central United States that extends from the northern to southeastern region of the United States. Contrary to most other even-numbered U.S. Highways, US 52 primarily follows ...

Postville Postville is a village in Allamakee and Clayton counties in the U.S. state of Iowa. It lies near the junction of four counties and at the intersection of U.S. Routes 18 and 52 and Iowa Highway 51, with airport facilities in the neighboring co ...

, then leaving 52 about east of Monona before crossing the Mississippi River into Wisconsin via the

Marquette–Joliet Bridge The Marquette–Joliet Bridge is a bridge crossing the Mississippi River, connecting Marquette, Iowa and Prairie du Chien, Wisconsin. Local residents refer to the bridge as the Prairie Bridge or the Marquette Bridge; both terms are used equally. ...

in the city of Marquette. U.S. 18 is the designated route of the Avenue of the Saints between Clear Lake and Charles City.

Wisconsin

Upon entry into Wisconsin at Prairie du Chien, US 18 is the terminus for

WIS 60 State Trunk Highway 60, often called Highway 60, STH-60 or WIS 60, is a state highway in the U.S. state of Wisconsin. It runs east–west in southern Wisconsin from Prairie du Chien on the Mississippi River at the Iowa state line to the ...

. The two routes are then concurrent until

Bridgeport Bridgeport is the most populous city and a major port in the U.S. state of Connecticut. With a population of 148,654 in 2020, it is also the fifth-most populous in New England. Located in eastern Fairfield County at the mouth of the Pequonnoc ...

where WIS 60 splits off to the east and US 18 crosses the

Wisconsin River The Wisconsin River is a tributary of the Mississippi River in the U.S. state of Wisconsin. At approximately 430 miles (692 km) long, it is the state's longest river. The river's name, first recorded in 1673 by Jacques Marquette as "Meskousi ...

and turns east on the other side. The route joins the

US 151 U.S. Highway 151 (US 151) is a United States Numbered Highway that runs through the states of Iowa and Wisconsin. The southern terminus for US 151 is at a junction with Interstate 80 (I-80) in Iowa County, Iowa, and its northern terminu ...

expressway in Dodgeville and the two remain concurrent east to

Madison Madison may refer to: People * Madison (name), a given name and a surname * James Madison (1751–1836), fourth president of the United States Place names * Madison, Wisconsin, the state capital of Wisconsin and the largest city known by this ...

(See

U.S. Route 151 in Wisconsin U.S. Highway 151 (US 151) is a United States Numbered Highway that runs through the states of Iowa and Wisconsin. The southern terminus for US 151 is at a junction with Interstate 80 (I-80) in Iowa County, Iowa, and its northern termi ...

for an interchange list). US 18 follows US 12 south of Madison and passes through or around Cambridge,

Jefferson Jefferson may refer to: Names * Jefferson (surname) * Jefferson (given name) People * Thomas Jefferson (1743–1826), third president of the United States * Jefferson (footballer, born 1970), full name Jefferson Tomaz de Souza, Brazilian foo ...

and Waukesha before terminating in Milwaukee at the junction of East Michigan Street and Lincoln Memorial Drive in downtown.

Major intersections

;Wyoming : in

Orin ORiN (Open Robot/Resource interface for the Network) is a standard network interface for FA (factory automation) systems. The Japan Robot Association proposed ORiN in 2002, and the ORiN Forum develops and maintains the ORiN standard. Background ...

. US 18/US 20 travel concurrently to Lusk. : in Lusk. The highways travel concurrently to the northeastern part of

. ;South Dakota : in

. The highways travel concurrently to Oelrichs. : west of Mission. The highways travel concurrently to Mission. : southeast of Witten. The highways travel concurrently to Colome. : east-southeast of

Fairfax Fairfax may refer to: Places United States * Fairfax, California * Fairfax Avenue, a major thoroughfare in Los Angeles, California * Fairfax District, Los Angeles, California, centered on Fairfax Avenue * Fairfax, Georgia * Fairfax, Indiana * Fa ...

. The highways travel concurrently to south of

Armour Armour (British English) or armor (American English; see spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, especially direct contact weapons or projectiles during combat, or fr ...

. : east of Menno : south-southwest of Worthing. The highways travel concurrently for approximately . ;Iowa : in Lincoln Township. The highways travel concurrently through the township. : in Sanborn. The highways travel concurrently to Franklin Township. : in Spencer. The highways travel concurrently through the city. : in Algona : in Garfield Township. The highways travel concurrently to

. : in Clear Lake. The highways travel concurrently to Lake Township. : in Mason City : in Floyd. The highways travel concurrently to

. : in New Hampton. The highways travel concurrently to Dresden Township. : in Post Township. The highways travel concurrently to Giard Township. ;Wisconsin : in Fennimore. The highways travel concurrently through the city. : east of Dodgeville. The highways travel concurrently to

. : in

. US 12/US 18 travel concurrently to Cambridge. US 14/US 18 travel concurrently through Madison. : in Madison : in Madison : northeast of Waukesha : in Wauwatosa. A southbound entrance allows access to . : Michigan Street/Lincoln Memorial Drive in Milwaukee

References

External links

Endpoints of U.S. Highway 18
{{DEFAULTSORT:18 United States Numbered Highway System U.S. Highways in South Dakota U.S. Highways in Wyoming