COUNTY · IA
Madison County, Iowa
Madison County is a county in Iowa with FIPS code 19121 and an estimated population of 16,971 (Census 2023), 41st largest of 99 in the state.
County facts
- Name
- Madison County
- State
- Iowa
- Type
- county
- FIPS code
- 19121
- State FIPS
- 19
- Population (2023)
- 16,971
- Change since 2020
- +2.1%
- State rank
- 41 of 99
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for Madison County?
Madison County, Iowa has the five-digit FIPS code 19121: 19 for the state and 121 for the county.
What state is Madison County in?
Madison County is in Iowa.
How do I know if an address is in this county?
Use the address lookup. ZIP codes and city names can cross county lines, so an address is the reliable check.
Sources: U.S. Census Bureau geographic reference files; Census Bureau Population Estimates, Vintage 2023. Last reviewed 2026-10-27.