Marysville is a city in and the county seat of Marshall County, Kansas, United States. As of the 2010 census, the city population was 3,294. Marysville was laid out in 1855 by Francis J. Marshall, and designated in that same year the county seat. It was incorporated as a city in 1861. Marysville was located on the Oregon Trail and the route of the Pony Express, the St. Joe Road, the Overland Stage, The Military Road, and the Otoe-Missouria Trail. British explorer Richard Francis Burton en route to California in 1860 noted: "Passing by Marysville, in old maps Palmetto City, a country-town which thrives by selling whiskey to ruffians of all descriptions ..." The old Pony Express Station still stands in downtown Marysville.