Charleston ranked as the 22nd largest city in the United States according to the 1860 Census, with a population of 40,522. As the 1814 burning of Washington had shown, America's coastal cities were vulnerable to a hostile fleet. Along the Atlantic seaboard the young Republic began building a series of substantial forts. Fort Sumter is the most famous of these sited on a shoal in Charleston harbor. There were also a series of smaller and older forts and bastions to protect it from any enemy ships.