| ZIP Codes: | 6 ZIP Codes (6 Standard, 0 PO Box, 0 Unique) [See All] |
| Area Codes: | 618 / 730 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 11:53:21 PM |
| Population: | 15,733 [See All] |
| FIPS: | 17159 |
| Land Area: | 398 sq mi |
| Water Area: | 2 sq mi |
| Coordinates: | 38.6966, -88.0593 |
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15,733 residents live across 6 ZIPs covering 398 sq mi, served by 6 distinct USPS-recognized cities.
Population moved from 16,293 to 15,733 from 2014 to 2024 — a -3.4% change. 2 ZIPs gained residents, 4 lost.
The county's wealthiest ZIP 62419 (Calhoun, $95,982 median) and poorest ZIP 62425 (Dundas, $54,400) are 16.6 miles apart — a 1.8× income gap across local geography.
Median home values vary 1.5× across this county — from $78,300 in 62452 (Parkersburg) to $116,500 in 62450 (Olney).
Density varies 11× across the county — from 7 people/sq mi in 62421 (Claremont) to 76 in 62450 (Olney).
Educational attainment ranges from 2.1% bachelor's+ in 62452 (Parkersburg) to 21.9% in 62450 (Olney) — the breadth of educational profiles across the area.
Within Illinois, this is the #66 most populous of 102 counties and ranks #67 for median household income .
Weighted by population, the typical household earns about $62,649 across the county — reflecting what a typical resident sees, not a simple ZIP average.
19.0% of adults age 25+ hold a bachelor's degree or higher (2,086 of 10,953 reporting).
6 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.
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 62450 | Olney | Standard | 12,327 | $62,096 | 162.9 | 1.3% |
| 62868 | Noble | Standard | 1,463 | $61,645 | 103.3 | -6.6% |
| 62425 | Dundas | Standard | 838 | $54,400 | 37.9 | 23.6% |
| 62452 | Parkersburg | Standard | 387 | $78,036 | 21.1 | -17.7% |
| 62421 | Claremont | Standard | 366 | $55,833 | 51.9 | -64.2% |
| 62419 | Calhoun | Standard | 352 | $95,982 | 20.9 | -10.2% |