| ZIP Codes: | 10 ZIP Codes (8 Standard, 2 PO Box, 0 Unique) [See All] |
| Area Codes: | 618 / 730 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 2:12:04 PM |
| Population: | 12,898 [See All] |
| FIPS: | 17189 |
| Land Area: | 524 sq mi |
| Water Area: | 1 sq mi |
| Coordinates: | 38.3505, -89.3419 |
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12,898 residents live across 10 ZIPs covering 524 sq mi, served by 10 distinct USPS-recognized cities.
Population moved from 13,652 to 12,898 from 2014 to 2024 — a -5.5% change. 4 ZIPs gained residents, 6 lost.
The county's wealthiest ZIP 62214 (Addieville, $104,063 median) and poorest ZIP 62876 (Radom, $55,833) are 26.3 miles apart — a 1.9× income gap across local geography.
Median home values vary 1.8× across this county — from $93,600 in 62848 (Irvington) to $169,100 in 62214 (Addieville).
Density varies 39× across the county — from 8 people/sq mi in 62831 (Du Bois) to 306 in 62848 (Irvington).
Educational attainment ranges from 12.1% bachelor's+ in 62848 (Irvington) to 32.5% in 62877 (Richview) — the breadth of educational profiles across the area.
Within Illinois, this is the #82 most populous of 102 counties and ranks #22 for median household income .
Weighted by population, the typical household earns about $78,838 across the county — reflecting what a typical resident sees, not a simple ZIP average.
23.9% of adults age 25+ hold a bachelor's degree or higher (2,205 of 9,212 reporting).
8 Standard delivery, 2 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.
Washington County lost 5.5% of residents between 2014 and 2024. ZIPs that shed the largest share:
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 62263 | Nashville | Standard | 4,819 | $71,690 | 151.1 | -9.0% |
| 62271 | Okawville | Standard | 1,873 | $82,746 | 64.3 | -10.6% |
| 62808 | Ashley | Standard | 1,602 | $69,015 | 74.6 | 4.8% |
| 62803 | Hoyleton | Standard | 1,132 | $81,823 | 52.7 | 15.7% |
| 62214 | Addieville | Standard | 1,048 | $104,063 | 54.2 | -4.7% |
| 62268 | Oakdale | Standard | 764 | $95,833 | 49.0 | 3.4% |
| 62848 | Irvington | PO Box | 738 | $80,156 | 2.4 | 8.1% |
| 62877 | Richview | Standard | 437 | $83,958 | 31.8 | -15.8% |
| 62831 | Du Bois | Standard | 339 | $79,464 | 43.3 | -37.0% |
| 62876 | Radom | PO Box | 146 | $55,833 | 0.0 | -17.0% |