The islands that became Allegheny Islands State Park were once one island, first purchased in 1788 by Samuel Hulings. The Hulings were prominent keelboatmen of the region and settled in several areas along the Allegheny River. The island came to be called Hulings Island or Lanes Island.
By 1864, boatmen were using the river islands for navigation and referred to them by their distance from the Point in downtown Pittsburgh. Hulings Island became 14-mile Island.
In 1932, to facilitate the passage of larger vessels, the U.S. Army Corps of Engineers constructed the Allegheny River Lock and Dam #3 that split 14-mile Island in two. Now known as the C.W. Bill Young Lock and Dam #3, the still functioning lock and dam are on the National Register of Historic Places.
The McDonough Corporation purchased 14-mile Island to mine it for sand and gravel for building and road construction projects, but the deposits proved to be too poor of quality and the islands were left in their natural state.
The McDonough Corporation donated 14-mile Island (both upper and lower) to the Western Pennsylvania Conservancy in the early 1970s. The Commonwealth of Pennsylvania purchased the islands in 1974 and established Allegheny Islands State Park on December 31, 1980.
Originally, five islands in the Allegheny River were part of a concept plan called “Allegheny River Edge Park,” including:
14-mile Island
12-mile Island
9-mile Island
Sycamore Island
Herrs Island
The acquisition of 12-mile Island failed due to existing lease camps and erosion problems. Acquisition plans for the remaining islands were abandoned and only 14-mile Island was ever purchased.
Two bridges cross the Allegheny River on the lower island.
The Bessemer and Lake Erie Railroad was established in 1900 by Andrew Carnegie to haul steel products from Conneaut, Ohio to the steel mills in Pittsburgh. The railroad was then sold to the U.S. Steel Corporation in 1901. The Bessemer and Lake Erie Railroad Bridge was built in 1918 by the American Bridge Company with a total length of 2,327 feet and 160 feet above river level.
The original Allegheny River Bridge was opened in 1951 to extend the Pennsylvania Turnpike (I-76) over the Allegheny River. The turnpike bridge was rebuilt in 2010 with a total length of 2,350 feet and 120 feet above river level.