Answer: Pea Patch Island
During the War of 1812, Philadelphia residents worried that a British fleet could easily make it up the unprotected Delaware River. So after the war, efforts were made to fortify islands in the river, including Pea Patch Island in Delaware City. Construction of a star-shaped fort began on the island, located 15 miles south of Wilmington, and the fort was completed in the 1820s. The fort caught fire and a new fort was built and used throughout the Civil War as a Union garrison and prison for Confederate soldiers.
Fort Delaware was returned to peacetime operations after the war and remained largely untouched until the late 1890s, when it was modernized to better meet the needs of then-current naval vessels. The fort saw moderate use during the world wars, then was closed and handed over to the State of Delaware. In 1951, with help from the Fort Delaware Society, it became a state park. Fort Delaware State Park on Pea Patch Island today serves as museum. The island is accessible by ferry where visitors can enjoy interactive exhibits, hiking, picnicking, and ghost tours.
Information on Pea Patch Island and Fort Delaware is available in HSP's library. Publications include Fort Delaware (call number Wd* 16 v.5), Opinion on Brief of Title of Pea Patch Island (call number UNJ* .481) and 130-year-old Fort Delaware Abandoned (call number Wd* 16 v.5). More images of the fort from the 1940s are also in the Philadelphia Record photograph morgue (#V7).
Image: Collage of close-up and wide angle views of Fort Delaware, 1944 photograph