| ZIP Codes: | 31 ZIP Codes (30 Standard, 1 PO Box, 0 Unique) [See All] |
| Area Codes: | 331 / 464 / 630 / 708 / 779 / 815 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 11:53:22 PM |
| Population: | 697,966 [See All] |
| FIPS: | 17197 |
| CBSA: | Chicago-Naperville-Elgin, IL-IN |
| Land Area: | 850 sq mi |
| Water Area: | 14 sq mi |
| Coordinates: | 41.5147, -88.0465 |
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697,966 residents live across 31 ZIPs covering 850 sq mi, served by 23 distinct USPS-recognized cities.
Population moved from 671,448 to 697,966 from 2014 to 2024 — a +3.9% change. 17 ZIPs gained residents, 13 lost.
The county's wealthiest ZIP 60564 (Naperville, $181,382 median) and poorest ZIP 60436 (Joliet, $62,961) are 16.2 miles apart — a 2.9× income gap across local geography.
Median home values vary 3.7× across this county — from $154,600 in 60484 (University Park) to $572,100 in 60564 (Naperville).
Density varies 54× across the county — from 78 people/sq mi in 60481 (Wilmington) to 4,206 in 60435 (Joliet).
Educational attainment ranges from 12.9% bachelor's+ in 60432 (Joliet) to 74.2% in 60564 (Naperville) — the breadth of educational profiles across the area.
Within Illinois, this is the #4 most populous of 102 counties and ranks #4 for median household income .
On the national stage, Will County is the #98 most populous US county .
Weighted by population, the typical household earns about $114,890 across the county — reflecting what a typical resident sees, not a simple ZIP average.
37.4% of adults age 25+ hold a bachelor's degree or higher (174,964 of 467,365 reporting).
30 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 |
|---|---|---|---|---|---|---|
| 60440 | Bolingbrook | Standard | 51,940 | $93,494 | 15.2 | -3.4% |
| 60435 | Joliet | Standard | 48,167 | $76,369 | 11.5 | -0.5% |
| 60586 | Plainfield | Standard | 47,834 | $131,637 | 17.8 | 1.6% |
| 60564 | Naperville | Standard | 47,016 | $181,382 | 16.1 | 12.4% |
| 60446 | Romeoville | Standard | 41,672 | $106,258 | 21.3 | 4.2% |
| 60451 | New Lenox | Standard | 37,361 | $137,404 | 25.4 | 7.9% |
| 60441 | Lockport | Standard | 36,844 | $103,374 | 27.9 | 3.0% |
| 60423 | Frankfort | Standard | 32,836 | $136,730 | 36.0 | 8.5% |
| 60544 | Plainfield | Standard | 27,306 | $108,304 | 24.5 | 8.3% |
| 60431 | Joliet | Standard | 27,138 | $122,870 | 12.3 | 21.5% |
| 60585 | Plainfield | Standard | 25,960 | $155,511 | 14.9 | 11.5% |
| 60448 | Mokena | Standard | 24,405 | $120,761 | 18.4 | -2.1% |
| 60491 | Homer Glen | Standard | 22,757 | $138,571 | 25.0 | 0.5% |
| 60490 | Bolingbrook | Standard | 22,156 | $150,531 | 9.9 | 8.9% |
| 60432 | Joliet | Standard | 20,465 | $64,917 | 8.8 | -3.7% |
| 60404 | Shorewood | Standard | 20,385 | $122,171 | 14.5 | 14.1% |
| 60436 | Joliet | Standard | 19,423 | $62,961 | 20.7 | 1.4% |
| 60403 | Crest Hill | Standard | 18,371 | $73,074 | 5.2 | -3.5% |
| 60503 | Aurora | Standard | 16,789 | $136,726 | 4.3 | -2.3% |
| 60433 | Joliet | Standard | 16,382 | $66,515 | 15.1 | -4.3% |
| 60417 | Crete | Standard | 14,901 | $91,952 | 36.8 | -4.9% |
| 60410 | Channahon | Standard | 14,239 | $118,976 | 27.5 | 11.9% |
| 60442 | Manhattan | Standard | 13,753 | $127,986 | 66.1 | 40.1% |
| 60481 | Wilmington | Standard | 11,195 | $79,042 | 142.8 | -6.6% |
| 60449 | Monee | Standard | 9,477 | $104,904 | 47.1 | 1.6% |
| 60401 | Beecher | Standard | 7,647 | $97,569 | 57.5 | -1.8% |
| 60484 | University Park | Standard | 6,762 | $73,266 | 9.9 | 0.4% |
| 60468 | Peotone | Standard | 5,809 | $104,625 | 72.0 | -0.3% |
| 60408 | Braidwood | Standard | 5,327 | $95,174 | 6.6 | -2.6% |
| 60421 | Elwood | Standard | 3,649 | $103,083 | 38.5 | -9.4% |
| 60434 | Joliet | PO Box | — | — | 0.0 | — |