Fort Delaware is a historic military fort located on Pea Patch Island in the Delaware River. Constructed between 1848 and 1859, it was designed to protect the city of Wilmington and the surrounding area from naval attacks. The fort features a unique design with thick walls and a series of casemates for artillery. During the American Civil War, Fort Delaware served as a prison for captured Confederate soldiers. It housed thousands of prisoners and was known for its harsh conditions. Today, the fort is a popular tourist destination, offering guided tours and educational programs about its history and significance.