Jacksonville is the largest city by population in the U.S. state of Florida, the 12th most populous city in the United States and the largest city by area in the contiguous United States. It is the county seat of Duval County, with which the city government consolidated in 1968. Consolidation gave Jacksonville its great size and placed most of its metropolitan population within the city limits; with an estimated population of 868,031 in 2015, it is the most populous city proper in Florida and the Southeast. Jacksonville is the principal city in the Jacksonville metropolitan area, with a population of 1,573,606 in 2015, the fourth largest metropolitan area in the state of Florida, after Miami, Tampa and Orlando.
Jacksonville is in the First Coast region of northeast Florida and is centered on the banks of the St. Johns River, about 25 miles (40 km) south of the Georgia state line and about 340 miles (550 km) north of Miami. The Jacksonville Beaches communities are along the adjacent Atlantic coast. The area was originally inhabited by the Timucua people, and in 1564 was the site of the French colony of Fort Caroline, one of the earliest European settlements in what is now the continental United States. Under British rule, settlement grew at the narrow point in the river where cattle crossed, known as Wacca Pilatka to the Seminole and the Cow Ford to the British. A platted town was established there in 1822, a year after the United States gained Florida from Spain; it was named after Andrew Jackson, the first military governor of the Florida Territory and seventh President of the United States.
Harbor improvements since the late 19th century have made Jacksonville a major military and civilian deep-water port. Its riverine location facilitates two United States Navy bases and the Port of Jacksonville, Florida's third largest seaport. The two US Navy bases, Blount Island Command and the nearby Naval Submarine Base Kings Bay form the third largest military presence in the United States. Significant factors in the local economy include services such as banking, insurance, healthcare and logistics. As with much of Florida, tourism is also important to the Jacksonville area, particularly tourism related to golf. People from Jacksonville may be called "Jacksonvillians" or "Jaxsons" (also spelled "Jaxons").