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. All ...

islands located in the middle of the Allegheny River northeast of

Pittsburgh Pittsburgh ( ) is a city in the Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County. It is the most populous city in both Allegheny County and Western Pennsylvania, the second-most populous city in Pennsylva ...

. 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 A ...

s of Oakmont and Plum, 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 w ...

(

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 Branch of the Canadian National Railway 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 (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 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 shoals 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 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 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 na ...

is allowed on the islands and they are open for visits by groups such as the Boy Scouts and Venture Outdoors. Allegheny Islands State Park is administered from the Region 2 Office in Prospect, Pennsylvania.

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