Fort Carroll

Fort Carroll is a 3.4-acre artificial island fort constructed in the Patapsco River south of Baltimore, Maryland, named for Charles Carroll of Carrollton, a signer of the Declaration of Independence. Designed by Brevet-Colonel Robert E. Lee and constructed beginning in 1848 under his supervision, the hexagonal fortification was built to protect Baltimore as part of the Third System defense program. The fort's exterior consists of large granite blocks with interior spaces defined by brick masonry and concrete, featuring curved granite stairs and brick archways of remarkable engineering craftsmanship. Though never completed and never used as a military installation, Fort Carroll was officially abandoned by the Army in 1921. Now listed on the National Register of Historic Places, the island remains an architectural testament to mid-19th-century American military engineering.