In 1821, Jackson County became part of the newly admitted state of Missouri. Jackson County was organized on December 15, 1826 and named for Andrew Jackson, U.S. Senator (and later President) from Tennessee. Its county seat was designated as Independence, which was at the time only a minuscule settlement near a spring. However, the rapid increase in Westward exploration and expansion ultimately made Independence the starting point for three of the great Westward Trails: the Santa Fe Trail, the Oregon Trail, and the California Trail. With the American Civil War and the coming of the railroads, nearby Kansas City ultimately eclipsed Independence, though both towns remain county seats.