| ZIP Codes: | 9 ZIP Codes (9 Standard, 0 PO Box, 0 Unique) [See All] |
| Area Codes: | 217 / 309 / 447 / 861 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 2:12:02 PM |
| Population: | 14,584 [See All] |
| FIPS: | 17125 |
| Land Area: | 657 sq mi |
| Water Area: | 26 sq mi |
| Coordinates: | 40.2735, -89.8866 |
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14,584 residents live across 9 ZIPs covering 657 sq mi, served by 9 distinct USPS-recognized cities.
Population moved from 16,185 to 14,584 from 2014 to 2024 — a -9.9% change. 0 ZIPs gained residents, 9 lost.
The county's wealthiest ZIP 61546 (Manito, $79,551 median) and poorest ZIP 62633 (Easton, $44,783) are 15.7 miles apart — a 1.8× income gap across local geography.
Median home values vary 2.0× across this county — from $69,000 in 62617 (Bath) to $136,400 in 61546 (Manito).
Educational attainment ranges from 2.6% bachelor's+ in 61567 (Topeka) to 22.0% in 61532 (Forest City) — the breadth of educational profiles across the area.
Within Illinois, this is the #74 most populous of 102 counties and ranks #87 for median household income .
Weighted by population, the typical household earns about $66,143 across the county — reflecting what a typical resident sees, not a simple ZIP average.
16.9% of adults age 25+ hold a bachelor's degree or higher (1,784 of 10,528 reporting).
9 Standard delivery, 0 PO Box only, 0 single-entity Unique ZIPs serve this county.
A frontier county — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.
Mason County lost 9.9% of residents between 2014 and 2024. ZIPs that shed the largest share:
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 62644 | Havana | Standard | 4,615 | $57,689 | 111.8 | -11.3% |
| 61546 | Manito | Standard | 3,849 | $79,551 | 106.2 | -7.8% |
| 62664 | Mason City | Standard | 2,922 | $70,509 | 113.2 | -4.2% |
| 62682 | San Jose | Standard | 684 | $60,125 | 47.7 | -3.3% |
| 62633 | Easton | Standard | 638 | $44,783 | 61.2 | -3.2% |
| 62655 | Kilbourne | Standard | 594 | $56,750 | 57.1 | -5.9% |
| 62617 | Bath | Standard | 524 | $56,667 | 78.0 | -27.7% |
| 61567 | Topeka | Standard | 411 | $68,750 | 50.9 | -21.3% |
| 61532 | Forest City | Standard | 347 | $71,544 | 30.5 | -33.0% |