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.
In 1851, Francis J. (Frank) Marshall of Weston, Missouri arrived on the bank of the Big Blue River. He came here to establish a trading post and to operate a ferry. On November 11, 1854 Marshall opened the first civilian Post Office in the Territory of Kansas. Marshall lent his name to the county, and Marysville was named to honor his wife Mary.
Mr. Marshall charged up to $5.00 per wagon and 25 cents per head of livestock to use his rope powered ferry across the Big Blue river, which operated until replaced by a bridge in 1864. He was a pro slavery candidate for governor in 1857.