The first continuously inhabited European-established settlement in the United States is St. Augustine, Florida, founded by the Spanish in 1565. This predates the English settlements at Jamestown (1607) and Plymouth (1620) by several decades. Established by Pedro Menéndez de Avilés, St. Augustine served as a military outpost and a missionary center for the Spanish Empire in North America. The city is famous for its Castillo de San Marcos, a 17th-century masonry fortress that never fell in battle. While indigenous cities like Cahokia existed long before European arrival, in the context of modern "U.S. cities" established during the colonial era, St. Augustine holds the undisputed title. Walking through its "Old Town" in 2026, visitors can still see the original street layouts and Spanish Colonial architecture that have survived over 450 years of hurricanes and conflicts.