Iowa became a territory in 1838, with Iowa City as its capital. Statehood came in 1846, with boundaries extended west to the Missouri River. Although population was only 100,000, the U.S. Congress needed a free state to admit in conjunction with the new slave state of Florida. Des Moines, more centralized than Iowa City, became the capital in 1857. Most of the early white settlement in Iowa came from Ohio and New York. Railroad line placement became important politically and commercially to the state. The success of a town would depend on its proximity to a rail line. River locations also were important.