27 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| New Castle | 1 | 21,087 | 21,902 | -0.77% | 2,538 | 8.31 | City |
| Neshannock township | 2 | 9,589 | 9,837 | -0.42% | 556 | 17.25 | Township |
| Ellwood City | 3 | 7,340 | 7,624 | -0.77% | 3,158 | 2.32 | Borough |
| Shenango township | 4 | 6,948 | 7,125 | -0.46% | 284 | 24.43 | Township |
| Union township | 5 | 4,837 | 4,985 | -0.47% | 508 | 9.52 | Township |
| North Beaver township | 6 | 3,955 | 3,957 | 0.15% | 93 | 42.37 | Township |
| Pulaski township | 7 | 3,020 | 3,094 | -0.3% | 98 | 30.68 | Township |
| Wilmington township | 8 | 2,641 | 2,663 | -0.04% | 134 | 19.74 | Township |
| Mahoning township | 9 | 2,612 | 2,705 | -0.61% | 109 | 23.89 | Township |
| Oakwood | 10 | 2,242 | 2,166 | -0.09% | 867 | 2.59 | CDP |
| Scott township | 11 | 2,124 | 2,171 | -0.52% | 108 | 19.75 | Township |
| New Wilmington | 12 | 2,097 | 2,097 | 0% | 1,990 | 1.05 | Borough |
| Perry township | 13 | 1,803 | 1,851 | -0.44% | 98 | 18.31 | Township |
| New Castle Northwest | 14 | 1,447 | 1,235 | 0.21% | 1,663 | 0.87 | CDP |
| Oakland | 15 | 1,303 | 1,456 | -1.29% | 977 | 1.33 | CDP |
| Pulaski township | 16 | 1,256 | 1,292 | -0.32% | 1,728 | 0.73 | Township |
| Little Beaver township | 17 | 1,194 | 1,224 | -0.33% | 59 | 20.37 | Township |
| Bessemer | 18 | 1,031 | 1,073 | -0.77% | 623 | 1.65 | Borough |
| New Bedford | 19 | 863 | 1,053 | -0.46% | 338 | 2.55 | CDP |
| West Pittsburg | 20 | 853 | 821 | 0.35% | 850 | 1 | CDP |
| Plain Grove township | 21 | 751 | 776 | -0.53% | 43 | 17.39 | Township |
| South New Castle | 22 | 624 | 648 | -0.79% | 1,926 | 0.32 | Borough |
| Wampum | 23 | 539 | 556 | -0.55% | 547 | 0.98 | Borough |
| New Castle township | 24 | 350 | 347 | 0.29% | 29 | 12.26 | Township |
| Enon Valley | 25 | 289 | 301 | -0.69% | 591 | 0.49 | Borough |
| Frizzleburg | 26 | 224 | 340 | -10.4% | 79 | 2.82 | CDP |
| Volant | 27 | 118 | 127 | -1.67% | 1,054 | 0.11 | Borough |
New Castle is the largest city in Lawrence County, with a population of 21,087.
Volant is the smallest city in Lawrence County.
There are 27 cities in Lawrence County, Pennsylvania.