St. Louis is an independent city and a major United States port on the eastern line of the state of Missouri. As of the 2010 census, the population was 319,294, and a 2012 estimate put the population at 318,172, making it the 58th-largest U.S. city in 2012. The metropolitan St. Louis area, known as Greater St. Louis (CSA), is the 19th-largest metropolitan area in the United States with a population of 2,900,605.The city of St. Louis was founded in 1764 by Pierre Laclède and Auguste Chouteau, and named for Louis IX of France. After the Louisiana Purchase, it became a major port on the Mississippi River; in the late 19th century, it became the fourth-largest city in the United States. It seceded from St. Louis County in March 1877, allowing it to become an independent city and limiting its political boundaries. In 1904, it hosted the Louisiana Purchase Exposition and the 1904 Summer Olympics. The city's population peaked in 1950, then began a long decline that continues in the 21st century. Immigration has increased, and it is the center of the largest Bosnian population in the world outside their homeland.