St. Louis is an independent city and the second-largest city in the U.S. state of Missouri. The city has a 2010 population of 319,294 and is the principal municipality of Greater St. Louis, population 2,892,874, the largest urban area in Missouri, the 4th largest urban area in the Midwest, and 15th-largest in the United States.

The city was founded in 1764 just south of the confluence of the Missouri and Mississippi rivers in what is today the Midwestern United States by colonial French traders Pierre Laclède de Liguest and René Auguste Chouteau, who named the settlement after King Louis IX of France. The early wealth of the city was based on the fur trade. The city, as well as the future state of Missouri, became part of the Spanish Empire after the French were defeated in the Seven Years' War. In 1800, the land was secretly transferred back to France, whose leader, Napoleon Bonaparte, sold it to the United States in 1803. Nicknamed the "Gateway to the West" for its role in the westward expansion of the United States, the city gave the moniker in 1965 to the new Gateway Arch built as part of the Jefferson National Expansion Memorial; the Arch has become the iconic image of St. Louis.