| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Kiskiminetas | 1 | 4,528 | 4,613 | 0.13% | 111 | 41 | Township |
| Kittanning | 2 | 3,940 | 3,923 | -0.03% | 3,956 | 1 | Borough |
| East Franklin | 3 | 3,690 | 3,811 | -0.24% | 119 | 31 | Township |
| Ford City | 4 | 2,725 | 2,859 | -0.91% | 4,225 | 1 | Borough |
| South Buffalo | 5 | 2,683 | 2,713 | 0.34% | 98 | 27 | Township |
| Cowanshannock | 6 | 2,656 | 2,727 | 0% | 58 | 46 | Township |
| North Buffalo | 7 | 2,605 | 2,691 | -0.23% | 105 | 25 | Township |
| Parks | 8 | 2,380 | 2,469 | -0.34% | 170 | 14 | Township |
| Gilpin | 9 | 2,329 | 2,405 | -0.17% | 142 | 16 | Township |
| Leechburg | 10 | 2,049 | 2,148 | -0.92% | 4,667 | 0 | Borough |
| Plumcreek | 11 | 2,039 | 2,106 | -0.1% | 48 | 42 | Township |
| Kittanning | 12 | 2,008 | 2,029 | 0.3% | 65 | 31 | Township |
| Rayburn | 13 | 1,713 | 1,773 | -0.17% | 145 | 12 | Township |
| Freeport | 14 | 1,656 | 1,738 | -0.96% | 1,304 | 1 | Borough |
| West Franklin | 15 | 1,653 | 1,706 | -0.12% | 63 | 26 | Township |
| Mahoning | 16 | 1,365 | 1,404 | 0.07% | 55 | 25 | Township |
| Sugarcreek | 17 | 1,334 | 1,349 | 0.08% | 50 | 27 | Township |
| West Leechburg | 18 | 1,225 | 1,265 | -0.57% | 1,244 | 1 | Borough |
| North Apollo | 19 | 1,201 | 1,257 | -0.91% | 2,212 | 1 | Borough |
| West Kittanning | 20 | 1,141 | 1,198 | -0.95% | 2,660 | 0 | Borough |
| South Bend | 21 | 978 | 1,008 | -0.2% | 43 | 23 | Township |
| Redbank | 22 | 932 | 972 | -0.32% | 29 | 32 | Township |
| Rural Valley | 23 | 791 | 828 | -0.88% | 375 | 2 | Borough |
| Boggs | 24 | 779 | 806 | -0.26% | 32 | 25 | Township |
| Bradys Bend | 25 | 760 | 783 | -0.13% | 60 | 13 | Township |
| Oklahoma | 26 | 758 | 787 | -0.66% | 1,249 | 1 | Borough |
| Parker | 27 | 668 | 698 | -0.89% | 699 | 1 | City |
| Burrell | 28 | 635 | 654 | -0.16% | 30 | 21 | Township |
| Valley | 29 | 627 | 651 | -0.32% | 43 | 15 | Township |
| Worthington | 30 | 561 | 588 | -0.88% | 815 | 1 | Borough |
| Parker | 31 | 558 | 580 | -0.71% | 24 | 23 | Township |
| Dayton | 32 | 523 | 548 | -0.95% | 1,391 | 0 | Borough |
| South Bethlehem | 33 | 459 | 482 | -1.08% | 3,020 | 0 | Borough |
| Perry | 34 | 364 | 367 | 0.55% | 24 | 15 | Township |
| Manorville | 35 | 361 | 377 | -0.82% | 3,574 | 0 | Borough |
| Pine | 36 | 347 | 359 | 0% | 80 | 4 | Township |
| Ford Cliff | 37 | 342 | 361 | -1.16% | 4,500 | 0 | Borough |
| Cadogan | 38 | 321 | 332 | 0.31% | 329 | 1 | Township |
| Applewold | 39 | 320 | 338 | -1.23% | 6,809 | 0 | Borough |
| Elderton | 40 | 319 | 334 | -0.93% | 988 | 0 | Borough |
| Freeport | 41 | 252 | 267 | -1.18% | 31 | 8 | Township |
| Atwood | 42 | 103 | 108 | -0.96% | 49 | 2 | Borough |
| Hovey | 43 | 70 | 74 | -1.41% | 38 | 2 | Township |
| Cherry Valley | 44 | 54 | 58 | -1.82% | 19 | 3 | Borough |
Kiskiminetas is the largest city in Armstrong County, with a population of 4,528.
Cherry Valley is the smallest city in Armstrong County, with a population of 54.
There are 44 cities in Armstrong County, Pennsylvania.