In 1849, Frank Marshall obtained permission from the U.S. government to establish a trading post and ferry before Kansas opened for settlement. Thousands of wagons lined up to cross the Blue River on the Oregon-California Trail as settlers headed northwest and gold seekers headed to California. Marshall's ferry transported three wagons at a time. John H. Clark wrote in 1852, “The Big Blue river is quite a stream of water and when it is high has to be ferried. At the time of our crossing the water had fallen so as to be fordable. Although a cold and wet morning the boys took to water like young ducks.” After Kansas Territory opened for settlement in 1854, Marshall's family joined him from Missouri. He named Marysville after his wife; the county was named for him. Marysville eventually became the county seat. In 1860 the town became a station on the Pony Express and later a stop on the Overland Stage Line.