37 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Northampton | 1 | 40,259 | 39,852 | 0.36% | 1,568 | 26 | Township |
| Easton | 2 | 31,018 | 28,087 | 1.93% | 7,276 | 4 | City |
| Palmer | 3 | 22,773 | 22,287 | 0.74% | 2,220 | 10 | Township |
| Forks | 4 | 16,833 | 16,130 | 1.02% | 1,393 | 12 | Township |
| Lower Saucon | 5 | 11,128 | 11,085 | 0.35% | 459 | 24 | Township |
| Lehigh | 6 | 10,865 | 10,759 | 0.46% | 370 | 29 | Township |
| Northampton | 7 | 10,641 | 10,369 | 0.51% | 4,306 | 2 | Borough |
| Moore | 8 | 9,488 | 9,327 | 0.56% | 255 | 37 | Township |
| Upper Nazareth | 9 | 8,489 | 8,142 | 0.43% | 1,161 | 7 | Township |
| Chestnut Hill | 10 | 8,116 | 6,135 | 7.14% | 2,677 | 3 | CDP |
| Lower Nazareth | 11 | 7,198 | 6,933 | 0.32% | 535 | 13 | Township |
| Williams | 12 | 6,734 | 6,570 | 0.96% | 371 | 18 | Township |
| Upper Mount Bethel | 13 | 6,457 | 6,442 | 0.36% | 152 | 42 | Township |
| Hellertown | 14 | 6,151 | 6,119 | 0.1% | 4,688 | 1 | Borough |
| Nazareth | 15 | 6,099 | 6,041 | 0.18% | 3,848 | 2 | Borough |
| Allen | 16 | 5,716 | 5,473 | 2.18% | 527 | 11 | Township |
| East Allen | 17 | 5,459 | 5,015 | 1.26% | 375 | 15 | Township |
| Bangor | 18 | 5,167 | 5,187 | -0.08% | 3,463 | 1 | Borough |
| Palmer Heights | 19 | 3,927 | 4,033 | 0.28% | 3,388 | 1 | CDP |
| Wind Gap | 20 | 3,826 | 2,819 | 5.54% | 2,857 | 1 | Borough |
| Eastlawn Gardens | 21 | 3,593 | 3,338 | 0.53% | 2,069 | 2 | CDP |
| Pen Argyl | 22 | 3,476 | 3,516 | -0.23% | 2,590 | 1 | Borough |
| Lower Mount Bethel | 23 | 2,924 | 2,916 | 0.24% | 123 | 24 | Township |
| Bath | 24 | 2,920 | 2,842 | 0.52% | 3,234 | 1 | Borough |
| Walnutport | 25 | 2,105 | 2,077 | 0.24% | 2,799 | 1 | Borough |
| Old Orchard | 26 | 1,674 | 1,807 | -2.96% | 2,293 | 1 | CDP |
| Roseto | 27 | 1,560 | 1,580 | -0.26% | 2,480 | 1 | Borough |
| Cherryville | 28 | 1,445 | 1,571 | -0.62% | 551 | 3 | CDP |
| Tatamy | 29 | 1,441 | 1,184 | 3.67% | 2,596 | 1 | Borough |
| Belfast | 30 | 1,232 | 1,305 | -0.16% | 1,002 | 1 | CDP |
| East Bangor | 31 | 1,108 | 1,121 | -0.27% | 1,333 | 1 | Borough |
| Stockertown | 32 | 912 | 915 | -0.11% | 940 | 1 | Borough |
| Portland | 33 | 484 | 486 | -0.21% | 1,002 | 0 | Borough |
| Martins Creek | 34 | 317 | 457 | -6.21% | 388 | 1 | CDP |
| Northampton | 35 | 292 | 305 | -1.02% | 8 | 36 | Township |
| Chapman | 36 | 220 | 220 | 0% | 667 | 0 | Borough |
| Ackermanville | 37 | 198 | 398 | -12% | 145 | 1 | CDP |
Northampton is the largest city in Northampton County, with a population of 40,259.
Ackermanville is the smallest city in Northampton County, with a population of 198.
There are 37 cities in Northampton County, Pennsylvania.