Jefferson County Flag

Jefferson County

State:
Kansas
County Seat:
Oskaloosa

Jefferson County's estimated 2025 population is 18,273 with a growth rate of -0.15% in the past year according to the most recent United States census data. Jefferson County is the 30th largest county in Kansas. The 2010 population was 19,120 and has seen a growth of -4.43% since that time.

18,273
Total Population
34
Population Density (mi²)
30
Population Rank (State)
-27 -0.15%
Annual Population Growth

Jefferson County Population

Demographics

Economics and Income Statistics