Rock is a census-designated place in Cowley County, Kansas, United States. As of the 2020 census, the population was 94. The post office was established August 12, 1870. In 1877, the Florence, El Dorado, and Walnut Valley Railroad Company built a branch line from Florence to El Dorado, in 1881 it was extended to Douglass, and later to Arkansas …Rock is a census-designated place in Cowley County, Kansas, United States. As of the 2020 census, the population was 94. The post office was established August 12, 1870. In 1877, the Florence, El Dorado, and Walnut Valley Railroad Company built a branch line from Florence to El Dorado, in 1881 it was extended to Douglass, and later to Arkansas City. The line was leased and operated by the Atchison, Topeka and Santa Fe Railway. The line from Florence to El Dorado was abandoned in 1942. The original branch line connected Florence, Burns, De Graff, El Dorado, Augusta, Douglass, Rock, Akron, Winfield, Arkansas City.