| ZIP Codes: | 8 ZIP Codes (8 Standard, 0 PO Box, 0 Unique) [See All] |
| Area Codes: | 309 / 861 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 2:12:04 PM |
| Population: | 14,945 [See All] |
| FIPS: | 17187 |
| Land Area: | 450 sq mi |
| Water Area: | 0 sq mi |
| Coordinates: | 40.8645, -90.6443 |
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14,945 residents live across 8 ZIPs covering 450 sq mi, served by 8 distinct USPS-recognized cities.
Population moved from 16,210 to 14,945 from 2014 to 2024 — a -7.8% change. 4 ZIPs gained residents, 4 lost.
The county's wealthiest ZIP 61417 (Berwick, $105,724 median) and poorest ZIP 61453 (Little York, $58,281) are 19.0 miles apart — a 1.8× income gap across local geography.
Median home values vary 1.4× across this county — from $87,500 in 61453 (Little York) to $123,500 in 61423 (Cameron).
Density varies 10× across the county — from 7 people/sq mi in 61417 (Berwick) to 70 in 61462 (Monmouth).
Educational attainment ranges from 7.5% bachelor's+ in 61423 (Cameron) to 42.8% in 61435 (Gerlaw) — the breadth of educational profiles across the area.
Within Illinois, this is the #72 most populous of 102 counties and ranks #43 for median household income .
Weighted by population, the typical household earns about $66,317 across the county — reflecting what a typical resident sees, not a simple ZIP average.
21.8% of adults age 25+ hold a bachelor's degree or higher (2,093 of 9,589 reporting).
8 Standard delivery, 0 PO Box only, 0 single-entity Unique ZIPs serve this county.
One ZIP holds the majority of this county's population — a sign of a county built around a single city or town.
Warren County lost 7.8% of residents between 2014 and 2024. ZIPs that shed the largest share:
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 61462 | Monmouth | Standard | 10,458 | $64,113 | 149.8 | -10.4% |
| 61473 | Roseville | Standard | 1,279 | $60,833 | 103.3 | -21.7% |
| 61447 | Kirkwood | Standard | 1,020 | $82,583 | 30.2 | 7.1% |
| 61453 | Little York | Standard | 677 | $58,281 | 44.4 | 16.5% |
| 61423 | Cameron | Standard | 638 | $78,594 | 42.9 | -16.6% |
| 61478 | Smithshire | Standard | 420 | $75,625 | 34.9 | 100.0% |
| 61435 | Gerlaw | Standard | 271 | — | 18.6 | 142.0% |
| 61417 | Berwick | Standard | 182 | $105,724 | 26.4 | -36.6% |