Jefferson County IA United States
| County FIPS | 19101 |
| Largest City | Fairfield |
| State | Iowa |
| Latitude | 41.0318 |
| Longitude | -91.9489 |
| Population | 15,705 |
| Density | 36.06 people per square mile |
| Time Zone | America/Chicago |
Median household: $61,620
Median individual: $35,651
Mode: 84.4% White
Median house value: $161,228.0
Median: 43.7 years old
With at least college degree: 43.3%
With STEM degree: 47.3%
Never married: 33.0%
Unemployed: 8.0%
All data comes from the SimpleMaps US Counties Database, 2026.
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