Lakin is a city in and the county seat of Kearny County, Kansas, United States. As of the 2020 census, the population of the city was 2,205. I…Lakin is a city in and the county seat of Kearny County, Kansas, United States. As of the 2020 census, the population of the city was 2,205. It is located along Highway 50. In spring 1873, John O'Loughlin, community founder, set up a trading post next to the newly completed Atchison, Topeka and Santa Fe Railway. The community was named by the AT&SF for David Long Lakin, former treasurer of the AT&SF. Lakin was designated county seat in 1888. A post office has been in operation in Lakin since March 1874.