St. Augustine (Spanish: San Agustín) is a city in the Southeastern United States, on the Atlantic coast of northeastern Florida. Founded in 1565 by Spanish explorers, it is the oldest continuously inhabited European-established settlement within the borders of the continental United States.

St. Augustine was founded on September 8, 1565, by Spanish admiral Pedro Menéndez de Avilés, Florida’s first governor. He named the settlement “San Agustín”, as his ships bearing settlers, troops, and supplies from Spain had first sighted land in Florida eleven days earlier on August 28, the feast day of St. Augustine. The city served as the capital of Spanish Florida for over 200 years. It was designated as the capital of British East Florida when the colony was established in 1763 until it was ceded to Spain in 1783.

Spain ceded Florida to the United States in 1819, and St. Augustine was designated the capital of the Florida Territory upon ratification of the Adams–Onís Treaty in 1821. The Florida National Guard made the city its headquarters that same year. The territorial government moved and made Tallahassee the capital of Florida in 1824.

The county seat of St. Johns County, St. Augustine is part of Florida’s First Coast region and the Jacksonville metropolitan area. Since the late 19th century, St. Augustine’s distinct historical character has made the city a tourist attraction.