During the 19th century, the defense of key cities and harbors along the coastlines of the United States depended on an extensive system of coastal fortifications built from Maine to Florida to protect the homeland from foreign naval powers. Fort Adams, completed in 1857 and named in honor of President John Adams, was one of the largest and most complex of these structures and a superlative example of military engineering. Designed for 468 cannon and 2400 troops, its massive walls and outerworks spread over twenty acres and incorporated elements of the art of fortification unmatched in the United States. Largely unaltered over the years, it still stands today symbolically guarding Narragansett Bay and Newport Harbor.