| ZIP Codes: | 38 ZIP Codes (20 Standard, 11 PO Box, 7 Unique) [See All] |
| Area Codes: | 609 / 640 |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 2:13:10 PM |
| Population: | 395,671 [See All] |
| FIPS: | 34021 |
| CBSA: | Trenton-Princeton, NJ |
| Land Area: | 252 sq mi |
| Water Area: | 5 sq mi |
| Coordinates: | 40.2486, -74.7059 |
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395,671 residents live across 38 ZIPs covering 252 sq mi, served by 10 distinct USPS-recognized cities.
Population moved from 379,366 to 391,279 from 2014 to 2024 — a +3.1% change. 13 ZIPs gained residents, 8 lost.
The county's wealthiest ZIP 08550 (Princeton Junction, $224,213 median) and poorest ZIP 08618 (Trenton, $50,390) are 9.1 miles apart — a 4.4× income gap across local geography.
Median home values vary 7.8× across this county — from $103,700 in 08609 (Trenton) to $807,200 in 08550 (Princeton Junction).
Density varies 1074× across the county — from 201 people/sq mi in 08525 (Hopewell) to 216,355 in 08544 (Princeton).
Most of the decade's growth concentrated around Trenton — top growth ZIPs averaged +29.1% over the past ten years ( 08608 , 08611 and 08610 ).
Educational attainment ranges from 8.2% bachelor's+ in 08609 (Trenton) to 85.5% in 08550 (Princeton Junction) — the breadth of educational profiles across the area.
Within New Jersey, this is the #12 most populous of 21 counties and ranks #10 for median household income .
Hosts 4 single-entity Unique ZIPs: 08544Princeton University ; 08541Educational Testing Service ; 08695Division Of Revenue ; and 08646Division Of Revenue .
Weighted by population, the typical household earns about $113,677 across the county — reflecting what a typical resident sees, not a simple ZIP average.
46.9% of adults age 25+ hold a bachelor's degree or higher (125,865 of 268,425 reporting). The most-educated ZIPs cluster around Princeton.
20 Standard delivery, 11 PO Box only, 7 single-entity Unique ZIPs serve this county.
8 ZIPs in this county where more than 60% of adults 25+ hold a bachelor's degree — typically college campuses, research enclaves, or tech corridors.
7 ZIP codes in this county serve a single facility — typically theme parks, universities, large corporations, airports, or government complexes.
Median household income spans 4.4× between the wealthiest and poorest ZIPs — a sign of significant intra-county inequality.
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 08540 | Princeton | Standard | 50,388 | $176,983 | 51.5 | 4.3% |
| 08618 | Trenton | Standard | 35,634 | $50,390 | 6.1 | -9.1% |
| 08610 | Trenton | Standard | 33,465 | $83,906 | 7.0 | 14.9% |
| 08611 | Trenton | Standard | 31,995 | $56,788 | 3.6 | 18.6% |
| 08648 | Lawrence Township | Standard | 31,323 | $125,514 | 16.7 | -3.2% |
| 08520 | Hightstown | Standard | 29,504 | $118,010 | 17.6 | 6.7% |
| 08619 | Trenton | Standard | 24,089 | $105,946 | 10.2 | 6.4% |
| 08638 | Trenton | Standard | 22,816 | $66,875 | 5.8 | -1.6% |
| 08550 | Princeton Junction | Standard | 21,067 | $224,213 | 20.3 | 8.0% |
| 08690 | Trenton | Standard | 18,841 | $127,339 | 7.0 | 0.9% |
| 08691 | Robbinsville | Standard | 16,607 | $132,520 | 27.1 | 8.9% |
| 08609 | Trenton | Standard | 15,938 | $68,238 | 1.4 | 10.7% |
| 08534 | Pennington | Standard | 13,272 | $175,573 | 22.1 | -0.4% |
| 08629 | Trenton | Standard | 13,013 | $82,646 | 0.8 | 2.2% |
| 08620 | Trenton | Standard | 11,621 | $105,368 | 8.9 | -6.4% |
| 08628 | Trenton | Standard | 9,831 | $108,158 | 8.0 | 5.0% |
| 08525 | Hopewell | Standard | 4,522 | $165,324 | 22.5 | -8.0% |
| 08544 | Princeton | Unique | 4,392 | — | 0.0 | — |
| 08560 | Titusville | Standard | 3,245 | $128,516 | 13.6 | -14.3% |
| 08542 | Princeton | Standard | 2,533 | $105,524 | 0.4 | -46.6% |
| 08608 | Trenton | Standard | 1,250 | $61,201 | 0.5 | 53.8% |
| 08561 | Windsor | PO Box | 325 | — | 1.2 | 1931.3% |
| 08541 | Princeton | Unique | — | — | 0.0 | — |
| 08543 | Princeton | PO Box | — | — | 0.0 | — |
| 08601 | Trenton | PO Box | — | — | 0.0 | — |
| 08603 | Trenton | PO Box | — | — | 0.0 | — |
| 08602 | Trenton | PO Box | — | — | 0.0 | — |
| 08607 | Trenton | PO Box | — | — | 0.0 | — |
| 08606 | Trenton | PO Box | — | — | 0.0 | — |
| 08604 | Trenton | PO Box | — | — | 0.0 | — |
| 08605 | Trenton | PO Box | — | — | 0.0 | — |
| 08650 | Trenton | PO Box | — | — | 0.0 | — |
| 08625 | Trenton | PO Box | — | — | 0.0 | — |
| 08695 | Trenton | Unique | — | — | 0.0 | — |
| 08646 | Trenton | Unique | — | — | 0.0 | — |
| 08666 | Trenton | Unique | — | — | 0.0 | — |
| 08645 | Trenton | Unique | — | — | 0.0 | — |
| 08647 | Trenton | Unique | — | — | 0.0 | — |