21 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Youngstown | 1 | 58,740 | 59,888 | -0.32% | 1,731 | 34 | City |
| Boardman | 2 | 39,679 | 40,117 | -0.09% | 1,716 | 23 | Township |
| Austintown | 3 | 35,581 | 35,966 | -0.09% | 1,457 | 24 | Township |
| Canfield | 4 | 16,764 | 16,902 | -0.05% | 651 | 26 | Township |
| Poland | 5 | 14,498 | 14,655 | -0.08% | 681 | 21 | Township |
| Struthers | 6 | 9,833 | 10,007 | -0.29% | 2,701 | 4 | City |
| Campbell | 7 | 7,708 | 7,837 | -0.27% | 2,074 | 4 | City |
| Canfield | 8 | 7,601 | 7,681 | -0.17% | 1,489 | 5 | City |
| Sebring | 9 | 4,113 | 4,176 | -0.24% | 1,648 | 2 | Village |
| Smith | 10 | 4,046 | 4,088 | -0.07% | 128 | 32 | Township |
| Milton | 11 | 3,527 | 3,558 | -0.06% | 159 | 22 | Township |
| Lordstown | 12 | 3,333 | 3,327 | 0.03% | 144 | 23 | Village |
| McDonald | 13 | 3,106 | 3,165 | -0.32% | 1,828 | 2 | Village |
| Poland | 14 | 2,408 | 2,453 | -0.29% | 1,474 | 2 | Village |
| Ellsworth | 15 | 2,104 | 2,126 | -0.05% | 83 | 25 | Township |
| Damascus | 16 | 1,814 | 1,804 | 0.06% | 60 | 30 | Township |
| New Middletown | 17 | 1,483 | 1,501 | -0.2% | 1,699 | 1 | Village |
| Coitsville | 18 | 1,243 | 1,259 | -0.16% | 97 | 13 | Township |
| Craig Beach | 19 | 1,058 | 1,073 | -0.19% | 1,349 | 1 | Village |
| Lowellville | 20 | 979 | 999 | -0.31% | 719 | 1 | Village |
| Beloit | 21 | 889 | 903 | -0.22% | 912 | 1 | Village |
Youngstown is the largest city in Mahoning County, with a population of 58,740.
Beloit is the smallest city in Mahoning County, with a population of 889.
There are 21 cities in Mahoning County, Ohio.