| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| New Castle | 1 | 21,017 | 21,891 | -0.75% | 2,530 | 8 | City |
| Neshannock | 2 | 9,574 | 9,836 | -0.26% | 555 | 17 | Township |
| Ellwood City | 3 | 7,307 | 7,611 | -0.75% | 3,144 | 2 | Borough |
| Shenango | 4 | 6,948 | 7,112 | -0.17% | 284 | 24 | Township |
| Union | 5 | 4,839 | 4,984 | -0.25% | 508 | 10 | Township |
| North Beaver | 6 | 3,940 | 3,954 | 0.15% | 93 | 42 | Township |
| Pulaski | 7 | 3,039 | 3,092 | -0.13% | 99 | 31 | Township |
| Mahoning | 8 | 2,649 | 2,705 | 0% | 111 | 24 | Township |
| Wilmington | 9 | 2,641 | 2,664 | -0.04% | 134 | 20 | Township |
| Scott | 10 | 2,133 | 2,167 | 0% | 108 | 20 | Township |
| New Wilmington | 11 | 2,081 | 2,100 | -0.14% | 1,974 | 1 | Borough |
| Perry | 12 | 1,805 | 1,852 | -0.22% | 99 | 18 | Township |
| Pulaski | 13 | 1,258 | 1,295 | -0.24% | 1,730 | 1 | Township |
| Little Beaver | 14 | 1,190 | 1,224 | -0.17% | 58 | 20 | Township |
| Bessemer | 15 | 1,030 | 1,072 | -0.77% | 623 | 2 | Borough |
| Plain Grove | 16 | 757 | 780 | -0.26% | 44 | 17 | Township |
| South New Castle | 17 | 630 | 655 | -0.79% | 1,944 | 0 | Borough |
| Wampum | 18 | 537 | 558 | -0.74% | 545 | 1 | Borough |
| New Castle | 19 | 349 | 349 | 0% | 28 | 12 | Township |
| Enon Valley | 20 | 299 | 306 | -0.66% | 611 | 0 | Borough |
| Volant | 21 | 122 | 127 | -0.81% | 1,089 | 0 | Borough |
New Castle is the largest city in Lawrence County, with a population of 21,017.
Volant is the smallest city in Lawrence County, with a population of 122.
There are 21 cities in Lawrence County, Pennsylvania.