21 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Youngstown | 1 | 58,931 | 59,888 | -0.32% | 1,737 | 34 | City |
| Boardman | 2 | 39,714 | 40,117 | -0.09% | 1,717 | 23 | Township |
| Austintown | 3 | 35,612 | 35,966 | -0.09% | 1,458 | 24 | Township |
| Canfield | 4 | 16,772 | 16,902 | -0.05% | 652 | 26 | Township |
| Poland | 5 | 14,510 | 14,655 | -0.08% | 682 | 21 | Township |
| Struthers | 6 | 9,862 | 10,007 | -0.29% | 2,709 | 4 | City |
| Campbell | 7 | 7,729 | 7,837 | -0.28% | 2,079 | 4 | City |
| Canfield | 8 | 7,614 | 7,681 | -0.18% | 1,492 | 5 | City |
| Sebring | 9 | 4,123 | 4,176 | -0.27% | 1,653 | 2 | Village |
| Smith | 10 | 4,049 | 4,088 | -0.07% | 128 | 32 | Township |
| Milton | 11 | 3,529 | 3,558 | -0.06% | 159 | 22 | Township |
| Lordstown | 12 | 3,332 | 3,327 | 0.03% | 144 | 23 | Village |
| McDonald | 13 | 3,116 | 3,165 | -0.32% | 1,834 | 2 | Village |
| Poland | 14 | 2,415 | 2,453 | -0.33% | 1,478 | 2 | Village |
| Ellsworth | 15 | 2,105 | 2,126 | -0.05% | 83 | 25 | Township |
| Damascus | 16 | 1,813 | 1,804 | 0.06% | 60 | 30 | Township |
| New Middletown | 17 | 1,486 | 1,501 | -0.2% | 1,702 | 1 | Village |
| Coitsville | 18 | 1,245 | 1,259 | -0.16% | 97 | 13 | Township |
| Craig Beach | 19 | 1,060 | 1,073 | -0.28% | 1,352 | 1 | Village |
| Lowellville | 20 | 982 | 999 | -0.41% | 722 | 1 | Village |
| Beloit | 21 | 891 | 903 | -0.34% | 914 | 1 | Village |
Youngstown is the largest city in Mahoning County, with a population of 58,931.
Beloit is the smallest city in Mahoning County, with a population of 891.
There are 21 cities in Mahoning County, Ohio.