32 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Kiskiminetas township | 1 | 4,440 | 4,603 | -0.85% | 109 | 40.67 | Township |
| Kittanning | 2 | 3,866 | 3,918 | -0.26% | 3,882 | 1 | Borough |
| East Franklin township | 3 | 3,668 | 3,809 | -1.03% | 119 | 30.89 | Township |
| Ford City | 4 | 2,732 | 2,854 | -0.87% | 4,236 | 0.65 | Borough |
| Cowanshannock township | 5 | 2,626 | 2,733 | -0.87% | 58 | 45.66 | Township |
| South Buffalo township | 6 | 2,618 | 2,707 | -0.83% | 96 | 27.25 | Township |
| North Buffalo township | 7 | 2,595 | 2,691 | -0.73% | 104 | 24.85 | Township |
| Parks township | 8 | 2,364 | 2,465 | -1% | 168 | 14.04 | Township |
| Gilpin township | 9 | 2,294 | 2,408 | -1.12% | 139 | 16.45 | Township |
| Leechburg | 10 | 2,054 | 2,146 | -0.87% | 4,679 | 0.44 | Borough |
| Plumcreek township | 11 | 2,019 | 2,105 | -0.98% | 48 | 42.38 | Township |
| Kittanning township | 12 | 1,956 | 2,028 | -0.81% | 64 | 30.71 | Township |
| Rayburn township | 13 | 1,699 | 1,772 | -0.99% | 143 | 11.85 | Township |
| Freeport | 14 | 1,662 | 1,739 | -0.89% | 1,309 | 1.27 | Borough |
| West Franklin township | 15 | 1,634 | 1,707 | -0.97% | 63 | 26.09 | Township |
| Mahoning township | 16 | 1,335 | 1,396 | -1.11% | 54 | 24.78 | Township |
| Sugarcreek township | 17 | 1,306 | 1,348 | -1.14% | 49 | 26.67 | Township |
| West Leechburg | 18 | 1,227 | 1,267 | -0.65% | 1,246 | 0.98 | Borough |
| North Apollo | 19 | 1,203 | 1,252 | -0.82% | 2,215 | 0.54 | Borough |
| West Kittanning | 20 | 1,138 | 1,190 | -0.87% | 2,653 | 0.43 | Borough |
| Rural Valley | 21 | 795 | 829 | -0.87% | 377 | 2.11 | Borough |
| Oklahoma | 22 | 763 | 788 | -0.65% | 1,257 | 0.61 | Borough |
| Parker | 23 | 671 | 698 | -0.74% | 702 | 0.96 | City |
| Worthington | 24 | 566 | 593 | -0.88% | 823 | 0.69 | Borough |
| Dayton | 25 | 530 | 552 | -0.75% | 1,410 | 0.38 | Borough |
| South Bethlehem | 26 | 467 | 486 | -0.85% | 3,072 | 0.15 | Borough |
| Manorville | 27 | 365 | 377 | -0.55% | 3,614 | 0.10 | Borough |
| Ford Cliff | 28 | 345 | 360 | -0.86% | 4,539 | 0.08 | Borough |
| Applewold | 29 | 324 | 338 | -0.92% | 6,894 | 0.05 | Borough |
| Elderton | 30 | 316 | 333 | -0.94% | 978 | 0.32 | Borough |
| Atwood | 31 | 105 | 110 | -0.94% | 50 | 2.09 | Borough |
| Cherry Valley | 32 | 55 | 59 | -1.79% | 20 | 2.82 | Borough |
Kiskiminetas township is the largest city in Armstrong County, with a population of 4,440.
Cherry Valley is the smallest city in Armstrong County.
There are 32 cities in Armstrong County, Pennsylvania.