Tarkio is a city in Tarkio Township, Atchison County, Missouri, United States. The population was 1,583 at the 2010 census. It was platted in 1880 and incorporated in 1881. The name "Tarkio" is from a Native American word meaning "place where walnuts grow". Historically, the economy of the city was based on agriculture and its status as a college town.