
Jefferson
- County:
- Greene County
- County Seat:
- Yes
- Area (mi²):
- 6.016
- State:
- Iowa
Jefferson is a city located in Greene County, Iowa. Jefferson has a 2025 population of 4,046. It is also the county seat of .Jefferson is currently declining at a rate of -0.66% annually and its population has decreased by -3.21% since the most recent census, which recorded a population of 4,180 in 2020.
The average household income in Jefferson is $73,678 with a poverty rate of 8.42%. The median age in Jefferson is 51.5 years: 43.5 years for males, and 57.4 years for females.