| ZIP Codes: | 45 ZIP Codes (37 Standard, 6 PO Box, 2 Unique) [See All] |
| Area Codes: | 609 / 640 / 732 / 848 / 908 |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 2:13:10 PM |
| Population: | 863,519 [See All] |
| FIPS: | 34023 |
| CBSA: | New York-Newark-Jersey City, NY-NJ |
| Land Area: | 308 sq mi |
| Water Area: | 9 sq mi |
| Coordinates: | 40.4894, -74.3924 |
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863,519 residents live across 45 ZIPs covering 308 sq mi, served by 34 distinct USPS-recognized cities.
Population moved from 816,893 to 863,519 from 2014 to 2024 — a +5.7% change. 28 ZIPs gained residents, 8 lost.
The county's wealthiest ZIP 08824 (Kendall Park, $174,776 median) and poorest ZIP 08861 (Perth Amboy, $64,491) are 17.2 miles apart — a 2.7× income gap across local geography.
Median home values vary 2.5× across this county — from $278,800 in 08832 (Keasbey) to $704,100 in 08536 (Plainsboro).
Density varies 20× across the county — from 545 people/sq mi in 08512 (Cranbury) to 11,037 in 08861 (Perth Amboy).
Educational attainment ranges from 16.4% bachelor's+ in 08861 (Perth Amboy) to 80.9% in 08536 (Plainsboro) — the breadth of educational profiles across the area.
Within New Jersey, this is the #2 most populous of 21 counties and ranks #9 for median household income with the #7 fastest decade growth .
On the national stage, Middlesex County is the #68 most populous US county .
Weighted by population, the typical household earns about $112,971 across the county — reflecting what a typical resident sees, not a simple ZIP average.
45.4% of adults age 25+ hold a bachelor's degree or higher (270,328 of 595,567 reporting).
37 Standard delivery, 6 PO Box only, 2 single-entity Unique ZIPs serve this county.
7 ZIPs in this county where more than 60% of adults 25+ hold a bachelor's degree — typically college campuses, research enclaves, or tech corridors.
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 08854 | Piscataway | Standard | 61,088 | $127,806 | 19.3 | 6.1% |
| 08861 | Perth Amboy | Standard | 59,351 | $64,491 | 5.4 | 9.6% |
| 08901 | New Brunswick | Standard | 57,263 | $65,810 | 6.1 | 2.2% |
| 08831 | Monroe Township | Standard | 55,658 | $109,042 | 51.8 | 16.7% |
| 08816 | East Brunswick | Standard | 49,360 | $143,586 | 21.6 | 5.8% |
| 08817 | Edison | Standard | 49,020 | $110,808 | 10.5 | 9.4% |
| 08902 | North Brunswick | Standard | 43,932 | $121,071 | 14.1 | 4.0% |
| 08857 | Old Bridge | Standard | 40,891 | $109,312 | 24.3 | 1.1% |
| 08820 | Edison | Standard | 39,978 | $171,363 | 10.5 | 0.8% |
| 07008 | Carteret | Standard | 25,526 | $97,021 | 4.9 | 7.4% |
| 08859 | Parlin | Standard | 25,448 | $99,882 | 4.8 | 20.1% |
| 07080 | South Plainfield | Standard | 24,411 | $130,205 | 8.3 | 3.1% |
| 08879 | South Amboy | Standard | 23,556 | $92,786 | 8.1 | 2.9% |
| 08536 | Plainsboro | Standard | 20,817 | $137,607 | 7.6 | 4.7% |
| 07095 | Woodbridge | Standard | 20,756 | $104,926 | 4.2 | 0.3% |
| 08872 | Sayreville | Standard | 20,204 | $97,489 | 9.5 | -2.1% |
| 08830 | Iselin | Standard | 19,551 | $109,500 | 3.2 | 8.5% |
| 08837 | Edison | Standard | 19,437 | $102,605 | 9.8 | 17.1% |
| 07067 | Colonia | Standard | 18,587 | $122,713 | 4.0 | 3.5% |
| 08840 | Metuchen | Standard | 18,206 | $146,635 | 3.2 | 9.7% |
| 08852 | Monmouth Junction | Standard | 18,062 | $133,209 | 14.3 | 4.8% |
| 07001 | Avenel | Standard | 17,121 | $101,670 | 3.4 | -2.0% |
| 08882 | South River | Standard | 16,124 | $96,147 | 3.0 | -0.3% |
| 08904 | Highland Park | Standard | 15,121 | $104,694 | 1.9 | 6.3% |
| 08846 | Middlesex | Standard | 14,645 | $105,000 | 3.5 | 6.4% |
| 08812 | Dunellen | Standard | 14,224 | $118,316 | 4.5 | -1.5% |
| 08824 | Kendall Park | Standard | 13,366 | $174,776 | 4.4 | 5.1% |
| 08512 | Cranbury | Standard | 12,928 | $118,587 | 23.7 | 22.3% |
| 08863 | Fords | Standard | 12,771 | $115,861 | 2.2 | 3.3% |
| 08850 | Milltown | Standard | 8,538 | $141,601 | 2.3 | 0.6% |
| 08884 | Spotswood | Standard | 8,187 | $104,702 | 2.5 | -2.1% |
| 08810 | Dayton | Standard | 7,952 | $151,902 | 5.1 | -10.7% |
| 07064 | Port Reading | Standard | 3,481 | $133,854 | 1.9 | -9.3% |
| 07077 | Sewaren | Standard | 3,248 | $108,948 | 1.1 | 38.7% |
| 08828 | Helmetta | Standard | 2,459 | $98,952 | 0.9 | 2.9% |
| 08832 | Keasbey | Standard | 2,252 | — | 2.4 | -2.8% |
| 08818 | Edison | PO Box | — | — | 0.0 | — |
| 08855 | Piscataway | PO Box | — | — | 0.0 | — |
| 08862 | Perth Amboy | PO Box | — | — | 0.0 | — |
| 08899 | Edison | Standard | — | — | 0.2 | — |
| 08989 | New Brunswick | Unique | — | — | 0.0 | — |
| 08906 | New Brunswick | PO Box | — | — | 0.0 | — |
| 08903 | New Brunswick | PO Box | — | — | 0.0 | — |
| 08933 | New Brunswick | Unique | — | — | 0.0 | — |
| 08871 | Sayreville | PO Box | — | — | 0.0 | — |