| ZIP Codes: | 19 ZIP Codes (18 Standard, 1 PO Box, 0 Unique) [See All] |
| Area Codes: | 224 / 779 / 815 / 847 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 11:53:20 PM |
| Population: | 328,030 [See All] |
| FIPS: | 17111 |
| CBSA: | Chicago-Naperville-Elgin, IL-IN |
| Land Area: | 637 sq mi |
| Water Area: | 9 sq mi |
| Coordinates: | 42.3010, -88.3571 |
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328,030 residents live across 19 ZIPs covering 637 sq mi, served by 16 distinct USPS-recognized cities.
Population moved from 324,650 to 328,030 from 2014 to 2024 — a +1.0% change. 9 ZIPs gained residents, 9 lost.
The county's wealthiest ZIP 60012 (Crystal Lake, $159,375 median) and poorest ZIP 60033 (Harvard, $68,633) are 18.3 miles apart — a 2.3× income gap across local geography.
Median home values vary 2.1× across this county — from $203,300 in 60033 (Harvard) to $417,300 in 60012 (Crystal Lake).
Density varies 45× across the county — from 66 people/sq mi in 60034 (Hebron) to 2,933 in 60156 (Lake In The Hills).
Educational attainment ranges from 16.2% bachelor's+ in 60097 (Wonder Lake) to 58.7% in 60012 (Crystal Lake) — the breadth of educational profiles across the area.
Within Illinois, this is the #6 most populous of 102 counties and ranks #6 for median household income .
Weighted by population, the typical household earns about $106,081 across the county — reflecting what a typical resident sees, not a simple ZIP average.
35.9% of adults age 25+ hold a bachelor's degree or higher (82,074 of 228,769 reporting).
18 Standard delivery, 1 PO Box only, 0 single-entity Unique ZIPs serve this county.
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 60014 | Crystal Lake | Standard | 48,590 | $109,016 | 27.0 | 0.4% |
| 60098 | Woodstock | Standard | 33,130 | $91,062 | 107.3 | 2.5% |
| 60102 | Algonquin | Standard | 32,286 | $132,949 | 18.6 | -1.2% |
| 60050 | Mchenry | Standard | 31,781 | $88,812 | 26.6 | -1.5% |
| 60142 | Huntley | Standard | 29,692 | $89,735 | 39.4 | 9.7% |
| 60156 | Lake In The Hills | Standard | 28,800 | $117,151 | 9.8 | -0.1% |
| 60013 | Cary | Standard | 26,694 | $120,604 | 14.9 | 1.7% |
| 60051 | Mchenry | Standard | 24,621 | $100,762 | 37.5 | -0.7% |
| 60033 | Harvard | Standard | 12,999 | $68,633 | 116.6 | -5.0% |
| 60152 | Marengo | Standard | 12,417 | $98,451 | 94.7 | -3.2% |
| 60012 | Crystal Lake | Standard | 12,368 | $159,375 | 17.0 | 9.3% |
| 60097 | Wonder Lake | Standard | 11,983 | $93,397 | 18.4 | 10.1% |
| 60081 | Spring Grove | Standard | 9,088 | $116,706 | 22.7 | -8.8% |
| 60021 | Fox River Grove | Standard | 4,996 | $119,176 | 2.3 | -12.7% |
| 60071 | Richmond | Standard | 3,851 | $74,426 | 26.9 | 10.6% |
| 60034 | Hebron | Standard | 2,033 | $87,188 | 31.0 | 13.3% |
| 60180 | Union | Standard | 1,831 | $110,070 | 20.4 | 20.5% |
| 60072 | Ringwood | Standard | 870 | $119,375 | 6.3 | -1.2% |
| 60039 | Crystal Lake | PO Box | — | — | 0.0 | — |