| ZIP Codes: | 5 ZIP Codes (5 Standard, 0 PO Box, 0 Unique) [See All] |
| Area Codes: | 779 / 815 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 2:11:58 PM |
| Population: | 50,366 [See All] |
| FIPS: | 17007 |
| CBSA: | Rockford, IL |
| Land Area: | 256 sq mi |
| Water Area: | 1 sq mi |
| Coordinates: | 42.3410, -88.8204 |
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50,366 residents live across 5 ZIPs covering 256 sq mi, served by 5 distinct USPS-recognized cities.
Population moved from 51,352 to 50,366 from 2014 to 2024 — a -1.9% change. 2 ZIPs gained residents, 3 lost.
The county's wealthiest ZIP 61011 (Caledonia, $127,273 median) and poorest ZIP 61008 (Belvidere, $76,604) are 10.5 miles apart — a 1.7× income gap across local geography.
Median home values vary 1.8× across this county — from $172,000 in 61012 (Capron) to $311,900 in 61011 (Caledonia).
Density varies 14× across the county — from 29 people/sq mi in 61038 (Garden Prairie) to 397 in 61008 (Belvidere).
Educational attainment ranges from 20.7% bachelor's+ in 61008 (Belvidere) to 39.6% in 61011 (Caledonia) — the breadth of educational profiles across the area.
Within Illinois, this is the #27 most populous of 102 counties and ranks #8 for median household income .
Weighted by population, the typical household earns about $85,361 across the county — reflecting what a typical resident sees, not a simple ZIP average.
23.1% of adults age 25+ hold a bachelor's degree or higher (7,776 of 33,710 reporting).
5 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.