Mason County, Illinois
County seat: Havana · Population 12,411 (2025) · 539 sq mi
Mason County is the 82nd most populous of Illinois's 102 counties, with 12,411 people (2025 estimate). Its county seat is Havana. It is part of the North Central region, one of the 10 Illinois economic development regions (DCEO). The map shows its 9 cities and towns and the 6 neighboring counties.
Mason County facts
- County seat
- Havana
- Population (2025 estimate)
- 12,411 −5.1% since 2020
- Land area
- 539 sq mi 48th largest of 102
- Water area
- 24 sq mi
- Population density
- 23 per sq mi
- Established
- 1841
- Same name
- One of 6 Mason Counties in the US
- Named after
- George Mason American delegate from Virginia to the U.S. Constitutional Convention (1725-1792)
- Largest city
- Havana 2,799
- Median household income
- $62,845
- Cities and towns
- 9 plus 1 CDPs
- ZIP codes
- 11
- Time zone
- Central
- FIPS code
- 17125
Cities and towns in Mason County
Mason County has 9 incorporated cities, towns and villages. Populations count the people living inside Mason County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Havana (county seat) | City | 2,799 | |
| Mason City | City | 1,956 | |
| Manito | Village | 1,473 | |
| Easton | Village | 298 | |
| San Jose | Village | 277 | Logan County |
| Bath | Village | 262 | |
| Kilbourne | Village | 256 | |
| Forest City | Village | 211 | |
| Topeka | Village | 50 |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Goofy Ridge | 125 |
ZIP codes in Mason County
11 ZIP codes reach into Mason County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 61532
- 61546 also Tazewell County
- 61567
- 62617
- 62627 also Cass County
- 62633
- 62644 also Fulton County
- 62655
- 62664
- 62671 also Logan County
- 62682 also Logan and Tazewell counties
Population of Mason County, 2020–2025
Mason County shrank by 671 people (−5.1%) between April 2020 and July 2025: 535 more deaths than births and a net loss of 126 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 13,050 |
| 2021 | 12,826 |
| 2022 | 12,710 |
| 2023 | 12,580 |
| 2024 | 12,489 |
| 2025 | 12,411 |
Neighboring counties
- Menard County southeast · 11,863 people
- Cass County southwest · 12,463 people
- Tazewell County northeast · 130,049 people
- Fulton County northwest · 32,901 people
- Logan County east · 27,182 people
- Schuyler County west · 6,657 people
Printable Mason County map
The PDF is a vector file with real text: it prints sharp on Letter paper and you can search it for a town. The PNG is 2400 pixels wide for slides and documents. Both are free to use with a credit to WhichCounty.
- PDF (Letter) (101 KB)
- PNG (2400 px) (76 KB)
Paste this code to embed the map on your site:
Sources
- Boundaries: U.S. Census Bureau, 2025 Cartographic Boundary Files (1:500,000).
- Population: Census Bureau county and city estimates, Vintage 2025. CDP populations: American Community Survey 2020–2024.
- Places and ZIP codes: Census Bureau 2026 Gazetteer and 2020 ZIP Code Tabulation Area relationship files.
- County seat, founding year and name origin: Wikidata (CC0), checked against state sources.
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