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.

Name 2020 Population Growth Since 2010
Johnson County610,09711.81%
Sedgwick County514,2433.03%
Shawnee County176,151-1.23%
Wyandotte County165,3464.89%
Douglas County123,05010.66%
Leavenworth County81,9927.17%
Riley County73,1452.22%
Butler County66,6231.09%
Reno County61,650-4.49%
Saline County54,145-2.94%
Crawford County38,995-0.45%
Finney County36,127-2.24%
Cowley County34,942-3.77%
Miami County34,2144.05%
Harvey County33,804-2.70%
Lyon County33,530-0.35%
Ford County33,088-2.71%
Montgomery County31,584-10.66%
Geary County30,516-13.41%
Ellis County28,5920.59%
McPherson County28,265-2.96%
Franklin County25,579-1.56%
Barton County25,469-7.97%
Pottawatomie County24,88714.54%
Sumner County22,792-5.49%
Seward County20,942-8.84%
Cherokee County19,817-7.94%
Labette County19,588-9.04%
Jefferson County18,945-1.01%
Dickinson County18,467-6.60%
Osage County16,163-0.69%
Atchison County15,977-5.22%
Neosho County15,797-4.11%
Bourbon County14,607-3.49%
Jackson County13,198-1.96%
Allen County12,296-7.98%
Marion County11,906-6.03%
Nemaha County10,2691.06%
Linn County9,8582.40%
Marshall County9,770-3.37%
Brown County9,570-3.99%
Rice County9,397-7.09%
Pratt County9,108-5.53%
Wilson County8,571-8.74%
Cloud County8,299-12.82%
Coffey County8,243-3.98%
Clay County7,959-6.91%
Anderson County7,914-2.33%
Doniphan County7,716-3.07%
Thomas County7,473-5.76%
Kingman County7,304-7.04%
Wabaunsee County7,019-0.43%
Grant County6,972-10.90%
Russell County6,863-1.94%
Pawnee County6,346-9.08%
Gray County6,1071.34%
Mitchell County6,068-4.23%
Greenwood County5,977-10.52%
Ellsworth County5,974-8.32%
Sherman County5,801-3.61%
Ottawa County5,738-5.87%
Morris County5,631-4.85%
Stevens County5,531-3.84%
Norton County5,418-4.36%
Harper County5,352-10.90%
Washington County5,328-7.88%
Phillips County5,151-8.57%
Rooks County4,905-5.56%
Scott County4,805-3.13%
Republic County4,642-5.99%
Barber County4,250-12.41%
Stafford County4,120-6.98%
Kearny County3,949-1.32%
Haskell County3,929-8.05%
Meade County3,918-14.75%
Smith County3,537-8.37%
Osborne County3,313-13.95%
Chautauqua County3,271-10.36%
Woodson County3,259-1.51%
Rush County3,149-4.98%
Lincoln County2,967-8.54%
Logan County2,8643.24%
Decatur County2,857-3.38%
Jewell County2,813-8.16%
Ness County2,764-10.95%
Edwards County2,761-9.59%
Trego County2,683-10.75%
Cheyenne County2,600-4.20%
Hamilton County2,581-4.65%
Gove County2,576-4.31%
Chase County2,571-7.62%
Rawlins County2,5542.32%
Kiowa County2,546-0.90%
Sheridan County2,5370.28%
Morton County2,513-22.44%
Elk County2,480-13.50%
Graham County2,466-5.23%
Wichita County2,055-8.18%
Clark County2,017-8.28%
Stanton County1,903-15.23%
Hodgeman County1,756-8.54%
Comanche County1,710-9.28%
Lane County1,588-8.53%
Wallace County1,457-1.55%
Greeley County1,215-3.42%