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 US 50/US 400. 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.