50 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Hamilton | 1 | 94,962 | 92,302 | 1.12% | 2,407 | 39 | Township |
| Hamilton | 2 | 94,962 | 92,048 | 1.12% | 2,407 | 39 | Township |
| Trenton | 3 | 92,003 | 90,810 | 0.89% | 12,096 | 8 | City |
| Trenton | 4 | 92,003 | 90,546 | 0.89% | 12,096 | 8 | City |
| Trenton | 5 | 91,354 | 90,810 | 0.18% | 12,011 | 8 | City |
| Trenton | 6 | 91,354 | 90,546 | 0.18% | 12,011 | 8 | City |
| Ewing | 7 | 36,468 | 37,315 | 1.7% | 2,398 | 15 | Township |
| Ewing | 8 | 36,468 | 37,290 | 1.7% | 2,398 | 15 | Township |
| West Windsor | 9 | 33,559 | 29,510 | 4.09% | 1,314 | 26 | Township |
| West Windsor | 10 | 33,559 | 29,530 | 4.09% | 1,314 | 26 | Township |
| Lawrence | 11 | 32,587 | 33,086 | 0.61% | 1,500 | 22 | Township |
| Lawrence | 12 | 32,587 | 33,053 | 0.61% | 1,500 | 22 | Township |
| Princeton | 13 | 32,260 | 30,689 | 2.59% | 1,798 | 18 | Township |
| Princeton | 14 | 32,260 | 30,629 | 2.59% | 1,798 | 18 | Township |
| Princeton | 15 | 31,649 | 30,689 | 0.65% | 1,764 | 18 | Township |
| Princeton | 16 | 31,649 | 30,629 | 0.65% | 1,764 | 18 | Township |
| East Windsor | 17 | 30,710 | 30,038 | 0.9% | 1,973 | 16 | Township |
| East Windsor | 18 | 30,710 | 29,941 | 0.9% | 1,973 | 16 | Township |
| Hopewell | 19 | 18,223 | 17,495 | 1.71% | 314 | 58 | Township |
| Hopewell | 20 | 18,223 | 17,442 | 1.71% | 314 | 58 | Township |
| Robbinsville | 21 | 16,280 | 15,487 | 2.21% | 796 | 20 | Township |
| Robbinsville | 22 | 16,280 | 15,442 | 2.21% | 796 | 20 | Township |
| Princeton Meadows | 23 | 16,023 | 14,261 | 0.92% | 6,284 | 3 | CDP |
| Mercerville | 24 | 14,648 | 12,783 | 0.65% | 3,972 | 4 | CDP |
| Hamilton Square | 25 | 11,672 | 11,526 | -0.63% | 2,730 | 4 | CDP |
| Twin Rivers | 26 | 8,319 | 7,221 | 0.7% | 6,587 | 1 | CDP |
| Heathcote | 27 | 7,011 | 7,389 | 1.14% | 2,236 | 3 | CDP |
| Hightstown | 28 | 6,028 | 5,899 | 0.84% | 4,889 | 1 | Borough |
| Hightstown | 29 | 6,028 | 5,884 | 0.84% | 4,889 | 1 | Borough |
| Hightstown | 30 | 6,001 | 5,899 | 0.38% | 4,867 | 1 | Borough |
| Hightstown | 31 | 6,001 | 5,884 | 0.38% | 4,867 | 1 | Borough |
| The College New Jersey | 32 | 5,374 | 3,864 | 7.14% | 12,556 | 0 | CDP |
| Hopewell | 33 | 4,521 | 4,387 | 1.55% | 151 | 30 | Township |
| Hopewell | 34 | 4,521 | 4,377 | 1.55% | 151 | 30 | Township |
| Robbinsville Center | 35 | 4,044 | 2,978 | 7.15% | 6,309 | 1 | CDP |
| Lawrenceville | 36 | 3,727 | 3,515 | -0.29% | 3,577 | 1 | CDP |
| Pennington | 37 | 2,945 | 2,793 | 1.34% | 3,065 | 1 | Borough |
| Pennington | 38 | 2,945 | 2,787 | 1.34% | 3,065 | 1 | Borough |
| Pennington | 39 | 2,935 | 2,793 | 1% | 3,054 | 1 | Borough |
| Pennington | 40 | 2,935 | 2,787 | 1% | 3,054 | 1 | Borough |
| Ten Mile Run | 41 | 2,312 | 1,801 | 1.05% | 911 | 3 | CDP |
| Hopewell | 42 | 1,955 | 1,909 | 0.88% | 2,700 | 1 | Borough |
| Hopewell | 43 | 1,955 | 1,900 | 0.88% | 2,700 | 1 | Borough |
| Hopewell | 44 | 1,947 | 1,909 | 0.46% | 2,689 | 1 | Borough |
| Hopewell | 45 | 1,947 | 1,900 | 0.46% | 2,689 | 1 | Borough |
| Princeton Junction | 46 | 1,911 | 1,989 | -1.9% | 1,048 | 2 | CDP |
| Griggstown | 47 | 1,173 | 858 | 2.09% | 480 | 2 | CDP |
| Titusville | 48 | 839 | 817 | 7.15% | 1,793 | 0 | CDP |
| Windsor | 49 | 410 | 618 | 7.05% | 357 | 1 | CDP |
| East Rocky Hill | 50 | 397 | 335 | -1% | 95 | 4 | CDP |
Hamilton is the largest city in Mercer County, with a population of 94,962.
East Rocky Hill is the smallest city in Mercer County, with a population of 397.
There are 50 cities in Mercer County, New Jersey.