27 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| New Castle | 1 | 21,190 | 21,900 | -0.67% | 2,551 | 8 | City |
| Neshannock | 2 | 9,610 | 9,836 | -0.35% | 557 | 17 | Township |
| Ellwood City | 3 | 7,365 | 7,617 | -0.69% | 3,169 | 2 | Borough |
| Shenango | 4 | 6,972 | 7,127 | -0.37% | 285 | 24 | Township |
| Union | 5 | 4,847 | 4,986 | -0.43% | 509 | 10 | Township |
| North Beaver | 6 | 3,940 | 3,957 | -0.13% | 93 | 42 | Township |
| Pulaski | 7 | 3,041 | 3,095 | -0.03% | 99 | 31 | Township |
| Wilmington | 8 | 2,642 | 2,663 | -0.08% | 134 | 20 | Township |
| Mahoning | 9 | 2,623 | 2,703 | -0.46% | 110 | 24 | Township |
| Oakwood | 10 | 2,242 | 2,166 | -0.09% | 867 | 3 | CDP |
| Scott | 11 | 2,135 | 2,170 | -0.23% | 108 | 20 | Township |
| New Wilmington | 12 | 2,087 | 2,096 | -0.1% | 1,980 | 1 | Borough |
| Perry | 13 | 1,810 | 1,850 | -0.22% | 99 | 18 | Township |
| New Castle Northwest | 14 | 1,447 | 1,235 | 0.21% | 1,663 | 1 | CDP |
| Oakland | 15 | 1,303 | 1,456 | -1.29% | 977 | 1 | CDP |
| Pulaski | 16 | 1,252 | 1,291 | -0.4% | 1,722 | 1 | Township |
| Little Beaver | 17 | 1,188 | 1,225 | -0.5% | 58 | 20 | Township |
| Bessemer | 18 | 1,035 | 1,072 | -0.77% | 626 | 2 | Borough |
| New Bedford | 19 | 863 | 1,053 | -0.46% | 338 | 3 | CDP |
| West Pittsburg | 20 | 853 | 821 | 0.35% | 850 | 1 | CDP |
| Plain Grove | 21 | 752 | 776 | -0.53% | 43 | 17 | Township |
| South New Castle | 22 | 632 | 650 | -0.63% | 1,951 | 0 | Borough |
| Wampum | 23 | 538 | 556 | -0.74% | 546 | 1 | Borough |
| New Castle | 24 | 353 | 350 | 0.28% | 29 | 12 | Township |
| Enon Valley | 25 | 293 | 301 | -0.68% | 599 | 0 | Borough |
| Frizzleburg | 26 | 224 | 340 | -10.4% | 79 | 3 | CDP |
| Volant | 27 | 120 | 127 | -1.64% | 1,071 | 0 | Borough |
New Castle is the largest city in Lawrence County, with a population of 21,190.
Volant is the smallest city in Lawrence County, with a population of 120.
There are 27 cities in Lawrence County, Pennsylvania.