Allegheny Islands State Park is a Pennsylvania state park in Harmar Township, Allegheny County,

Pennsylvania Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...

in the United States. The undeveloped park is composed of three

alluvial Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluv ...

islands located in the middle of the

Allegheny River The Allegheny River ( ) is a long headwater stream of the Ohio River in western Pennsylvania and New York (state), New York. The Allegheny River runs from its headwaters just below the middle of Pennsylvania's northern border northwesterly into ...

northeast of

Pittsburgh Pittsburgh ( ) is a city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County, Pennsylvania, Allegheny County. It is the most populous city in both Allegheny County and Wester ...

. The islands are just north of the

borough A borough is an administrative division in various English-speaking countries. In principle, the term ''borough'' designates a self-governing walled town, although in practice, official use of the term varies widely. History In the Middle Ag ...

s of Oakmont and

Plum A plum is a fruit of some species in ''Prunus'' subg. ''Prunus'.'' Dried plums are called prunes. History Plums may have been one of the first fruits domesticated by humans. Three of the most abundantly cultivated species are not found i ...

, and southwest of Cheswick. ''Note: shows Allegheny River and its islands'' Bridges for the

Pennsylvania Turnpike The Pennsylvania Turnpike (Penna Turnpike or PA Turnpike) is a toll highway operated by the Pennsylvania Turnpike Commission (PTC) in the U.S. state of Pennsylvania. A controlled-access highway, it runs for across the state. The turnpike's we ...

(

Interstate 76 Interstate 76 may refer to: Interstate Highways in the United States * Interstate 76 (Colorado–Nebraska) * Interstate 76 (Ohio–New Jersey), running through Pennsylvania Video gaming * ''Interstate '76 ''Interstate '76'' is a vehicular ...

) and the

Bessemer and Lake Erie Railroad The Bessemer and Lake Erie Railroad is a class II railroad that operates in northwestern Pennsylvania and northeastern Ohio. The railroad's main route runs from the Lake Erie port of Conneaut, Ohio, to the Pittsburgh suburb of Penn Hills, Pen ...

Branch of the

Canadian National Railway The Canadian National Railway Company (french: Compagnie des chemins de fer nationaux du Canada) is a Canadian Class I freight railway headquartered in Montreal, Quebec, which serves Canada and the Midwestern and Southern United States. CN i ...

cross the Allegheny River at the middle island.

Islands

The park land on the islands has a total area of , with two islands downstream of the

Allegheny River Lock and Dam Three C.W. Bill Young Lock and Dam (formerly known as Allegheny River Lock and Dam No. 3) in Harmar Township, Allegheny County, Pennsylvania, and Plum, Pennsylvania, is a lock that was built in 1932. The lock and fixed-crest dam were built by the U.S. ...

(officially named the ''C. W. Bill Young Lock and Dam''), and the other island upstream. Twelve Mile Island is the farthest downstream (west) and has a number of houses and buildings on the western four-fifths of the island (the park land is the eastern end). The remaining two islands are both uninhabited and have no structures on them. They were originally one island named Fourteen Mile Island, but were split into two parts by the construction of the dam. Today the name Fourteen Mile Island is given to the middle island, just downstream (west) of the dam, and it is the site of the highway and railroad bridges. According to the

USGS The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, a ...

GNIS The Geographic Names Information System (GNIS) is a database of name and locative information about more than two million physical and cultural features throughout the United States and its territories, Antarctica, and the associated states of ...

, the last island (which was once part of Fourteen Mile Island) is unnamed (although it is still labeled "Fourteen Mile Island" on the

U.S. Army Corps of Engineers , colors = , anniversaries = 16 June (Organization Day) , battles = , battles_label = Wars , website = , commander1 = ...

navigation maps of the Allegheny River.) This unnamed island is the easternmost and the only one upstream of the dam. There are also five to seven

shoal In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body of water to near the surface. It ...

s near the islands, which are occasionally exposed. Twelve Mile Island and Fourteen Mile Island are named for their distances, and , up the Allegheny River from the

confluence In geography, a confluence (also: ''conflux'') occurs where two or more flowing bodies of water join to form a single channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main stem); o ...

of the Allegheny and

Monongahela River The Monongahela River ( , )—often referred to locally as the Mon ()—is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed August 15, 2011 river on the Allegheny Plateau in North Cen ...

s to form the

Ohio River The Ohio River is a long river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing southwesterly from western Pennsylvania to its mouth on the Mississippi River at the southern tip of Illino ...

in downtown Pittsburgh. They are two of six alluvial islands in the Allegheny River near Pittsburgh (for comparison, near Pittsburgh the Ohio River has only three islands and the Monongahela River has none). "The large number of islands in the Allegheny is a reflection of the large amount of glacially-derived sediment that was moved by the river."

Facilities

Allegheny Islands State Park was established on December 31, 1980. , it is undeveloped so that there are no facilities, and also no plans for future development. The park can only be accessed by boat.

Camping Camping is an outdoor activity involving overnight stays away from home, either without shelter or using basic shelter such as a tent, or a recreational vehicle. Typically, participants leave developed areas to spend time outdoors in more nat ...

is allowed on the islands and they are open for visits by groups such as the

Boy Scout A Scout (in some countries a Boy Scout, Girl Scout, or Pathfinder) is a child, usually 10–18 years of age, participating in the worldwide Scouting movement. Because of the large age and development span, many Scouting associations have split ...

s and

Venture Outdoors Venture may refer to: Arts and entertainment Music *The Ventures, an American instrumental rock band formed in 1958 *"A Venture", 1971 song by the band Yes *''Venture'', a 2010 EP by AJR Games * ''Venture'' (video game), a 1981 arcade g ...

. Allegheny Islands State Park is administered from the Region 2 Office in

Prospect, Pennsylvania Prospect is a borough in Butler County, Pennsylvania, United States. As of the 2010 census, the borough had a population of 1,169. Geography Prospect is located in western Butler County at (40.904113, -80.046430). U.S. Route 422, a limited-acce ...

Nearby state parks

The following state parks are within of Allegheny Islands State Park: *

Hillman State Park Hillman State Park is a Pennsylvania state park in Hanover Township, Washington County in the United States. It is about west of Pittsburgh. The park opened in the late 1960s and has been managed for hunting by the Pennsylvania Game Commiss ...

( Washington County) * Keystone State Park ( Westmoreland County) *

Point State Park Point State Park (locally known as The Point) is a Pennsylvania state park on in Downtown Pittsburgh, Allegheny County, Pennsylvania, USA, at the confluence of the Allegheny and Monongahela rivers, forming the Ohio River. Built on land acqu ...

(Allegheny County)

References

External links

{{Authority control Allegheny Islands Parks in the Pittsburgh metropolitan area Islands of the Allegheny River in Pennsylvania Protected areas established in 1980 Parks in Allegheny County, Pennsylvania Islands of Allegheny County, Pennsylvania 1980 establishments in Pennsylvania Protected areas of Allegheny County, Pennsylvania