Chapman is a city in Dickinson County, Kansas, United States. As of the 2020 census, the population of the city was 1,377. The first settlemen…Chapman is a city in Dickinson County, Kansas, United States. As of the 2020 census, the population of the city was 1,377. The first settlement was made at Chapman in 1868, and the same year Jackman's mill was built on Chapman creek a little northeast of the present town. James Streeter and S. M. Strickler laid out the town in 1871. It was named from the Chapman Creek.