There are 22 cities in Warren County, New Jersey.
Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)
City | Rank | 2024 Population | 2020 Population | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Phillipsburg | 1 | 15,358 | 15,224 | 0.2% | 4,813 | 3.2 | Town |
| Hackettstown | 2 | 10,128 | 10,232 | 0.03% | 2,804 | 3.6 | Town |
| Lopatcong township | 3 | 9,467 | 8,788 | 0.38% | 1,294 | 7.3 | Township |
| Mansfield township | 4 | 7,923 | 7,772 | 0.6% | 268 | 29.6 | Township |
| Washington borough | 5 | 7,342 | 7,281 | 0.1% | 3,736 | 2.0 | Borough |
| Washington township | 6 | 6,859 | 6,494 | 1.17% | 382 | 18.0 | Township |
| Blairstown township | 7 | 5,771 | 5,698 | 0.24% | 193 | 29.9 | Township |
| Independence township | 8 | 5,534 | 5,459 | 0.27% | 279 | 19.8 | Township |
| Greenwich township | 9 | 5,512 | 5,467 | 0.16% | 521 | 10.6 | Township |
| Allamuchy township | 10 | 5,458 | 5,345 | 0.22% | 273 | 20.0 | Township |
| White township | 11 | 4,734 | 4,602 | 0.64% | 173 | 27.4 | Township |
| Pohatcong township | 12 | 3,287 | 3,240 | 0.34% | 246 | 13.4 | Township |
| Franklin township | 13 | 3,007 | 2,965 | 0.23% | 128 | 23.4 | Township |
| Knowlton township | 14 | 2,935 | 2,887 | 0.31% | 119 | 24.7 | Township |
| Liberty township | 15 | 2,692 | 2,665 | 0.15% | 231 | 11.7 | Township |
| Belvidere | 16 | 2,542 | 2,517 | 0.24% | 1,754 | 1.4 | Town |
| Harmony township | 17 | 2,528 | 2,495 | 0.12% | 106 | 23.8 | Township |
| Oxford township | 18 | 2,472 | 2,441 | 0.33% | 415 | 6.0 | Township |
| Alpha borough | 19 | 2,354 | 2,326 | 0.26% | 1,400 | 1.7 | Borough |
| Frelinghuysen township | 20 | 2,230 | 2,197 | 0.27% | 94 | 23.6 | Township |
| Hope township | 21 | 1,857 | 1,832 | 0.32% | 103 | 18.1 | Township |
| Hardwick township | 22 | 1,611 | 1,593 | 0.06% | 43 | 37.5 | Township |
Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.
Phillipsburg is the largest city in Warren County.
Hardwick township is the smallest city in Warren County.
There are 22 cities in Warren County, New Jersey.