Population of Counties in Kansas (2020)
Of the 105 counties in Kansas, Johnson County is the most populous. Johnson County has a population of 597,555 people, about 20.52% of the state’s total population. Johnson County has grown about 9.51% since the 2010 Census. Sedgwick County is the second-largest county in Kansas and the only other county with over 500,000 people, with a population of 513,607 people. Sedgwick comprises 17.64% of the state’s population and has grown about 2.90% since the 2010 Census. Wyandotte County is the third-most populous county in Kansas, with a population of 165,324. Wyandotte County is also home to Kansas City. Wyandotte comprises about 5.68% of Kansas’s population and has grown 4.88% since the 2010 Census.
Kansas Counties with the Fewest Residents
Greeley County is the smallest county in Kansas in terms of population size, home to only 1,227 people. This is only 0.04% of the state’s total population. The population density in Greeley County is only 1.58 persons per square kilometer. While the county already has a very small population, it has declined by 2.46% since the 2010 Census.
The next two counties with the fewest residents are Wallace (1,503) and Lane (1,560), comprising only about 0.10% of Kansas’s total population together. Wallace County has a population density of just 1.65 persons per square kilometer and Lane County’s is 2.17 persons per square kilometer. While Wallace County has grown 1.55% since 2010, Lane County has shrunk by 10.14%.
Kansas Counties with Rapid Growth
Only one county in Kansas has experienced double-digit growth since 2010: Pottawatomie County. Pottawatomie County has grown by 11.73% since the Census. Despite this growth, its population is still relatively small at 24,277 people, just 0.83% of the state’s population.
The next three fastest-growing counties in Kansas are Johnson, Douglas, and Leavenworth. These counties have grown 9.51%, 9.21%, and 6.33% respectively since 2010.