Mason County, Illinois
Mason County is a county in Illinois. Its county FIPS code is 17125. Use the boundary map and neighboring areas below to check the jurisdiction you need.
- Official code
- 17125
- Representative coordinates
- 40.236993, -89.913575
- County type
- County
- County seat or government
- Havana
- Resident population, July 2025
- 12,411
- Land area
- 1,396.915 km²
- Water area
- 62.749 km²
- State
- Illinois
The representative point identifies this area. It is not a street address or a boundary survey.
Time zones in Mason County
| Time zone | Local time and UTC offset | Next clock change |
|---|---|---|
| America/Chicago | UTC-06:00 in January; UTC-05:00 in July. Enable JavaScript for the live clock. | Enable JavaScript for upcoming changes. |
Listed zones overlap the mapped area. A point lookup can distinguish sides of a boundary. Your device’s zone may differ.
Census ZIP areas
61532 · 61546 · 61567 · 62617 · 62627 · 62633 · 62644 · 62655 · 62664 · 62671 · 62682
These statistical areas overlap the boundary. They are not delivery assignments; confirm mailing details with USPS ZIP Code Lookup.
Official county information
Mason County government website ↗ is the next stop for county offices, tax, voting, jury and records information. A geographic lookup cannot determine eligibility, tax liability or a court obligation.
Cities, towns and communities
These areas overlap the mapped boundary; an overlap does not mean that every address belongs to both.
Areas sharing the mapped boundary
These areas touch this mapped boundary.
Before using this answer on a form
Use a precise point for address-level questions. A device accuracy circle can cross a boundary; confirm tax, voting or jury details with the responsible office.
Find the county at your current point, check its ZIP area, or find its physical time zone.