There are 105 counties in Kansas. 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.
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%.
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.