| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Robinson | 1 | 15,847 | 15,509 | 0.71% | 1,042 | 15 | Township |
| Indiana | 2 | 14,883 | 14,021 | 1.27% | 8,461 | 2 | Borough |
| Indiana | 3 | 7,482 | 7,251 | 0.84% | 426 | 18 | Township |
| Center | 4 | 4,306 | 4,382 | -0.55% | 107 | 40 | Township |
| Armagh | 5 | 4,112 | 4,021 | 0.59% | 44 | 93 | Township |
| Burrell | 6 | 3,413 | 3,481 | -0.61% | 143 | 24 | Township |
| Green | 7 | 3,378 | 3,414 | -0.3% | 64 | 53 | Township |
| Blairsville | 8 | 3,170 | 3,217 | -0.19% | 2,242 | 1 | Borough |
| Armstrong | 9 | 2,735 | 2,759 | -0.44% | 73 | 38 | Township |
| Rayne | 10 | 2,723 | 2,780 | -0.55% | 58 | 47 | Township |
| Cherryhill | 11 | 2,408 | 2,443 | -0.54% | 50 | 49 | Township |
| West Wheatfield | 12 | 2,104 | 2,139 | -0.52% | 67 | 32 | Township |
| East Wheatfield | 13 | 2,100 | 2,138 | -0.62% | 77 | 27 | Township |
| Conemaugh | 14 | 2,035 | 2,060 | -0.39% | 60 | 34 | Township |
| Pine | 15 | 1,828 | 1,854 | -0.49% | 59 | 31 | Township |
| South Mahoning | 16 | 1,786 | 1,818 | -0.67% | 63 | 29 | Township |
| Homer City | 17 | 1,705 | 1,728 | -0.18% | 3,089 | 1 | Borough |
| Robinson | 18 | 1,666 | 1,705 | -0.36% | 79 | 21 | Township |
| Brush Valley | 19 | 1,665 | 1,676 | -0.42% | 40 | 41 | Township |
| Young | 20 | 1,662 | 1,687 | -0.48% | 48 | 35 | Township |
| Canoe | 21 | 1,399 | 1,424 | -0.57% | 52 | 27 | Township |
| North Mahoning | 22 | 1,311 | 1,332 | -0.61% | 46 | 28 | Township |
| Clymer | 23 | 1,301 | 1,319 | -0.23% | 2,286 | 1 | Borough |
| West Mahoning | 24 | 1,301 | 1,322 | -0.61% | 45 | 29 | Township |
| Buffington | 25 | 1,215 | 1,226 | -0.25% | 40 | 31 | Township |
| Black Lick | 26 | 1,098 | 1,118 | -0.63% | 40 | 28 | Township |
| East Mahoning | 27 | 948 | 962 | -0.63% | 30 | 31 | Township |
| Banks | 28 | 890 | 900 | -0.34% | 28 | 32 | Township |
| West Lebanon | 29 | 862 | 834 | 1.06% | 2,227 | 0 | Township |
| Saltsburg | 30 | 759 | 771 | -0.26% | 3,667 | 0 | Borough |
| Grant | 31 | 626 | 636 | -0.63% | 23 | 27 | Township |
| Clymer | 32 | 600 | 619 | -0.33% | 18 | 34 | Township |
| Ernest | 33 | 409 | 417 | -0.24% | 1,778 | 0 | Borough |
| Marion Center | 34 | 403 | 408 | -0.25% | 542 | 1 | Borough |
| Creekside | 35 | 279 | 284 | -0.36% | 1,262 | 0 | Borough |
| Cherry Tree | 36 | 270 | 274 | -0.37% | 538 | 1 | Borough |
| Glen Campbell | 37 | 249 | 254 | -0.4% | 267 | 1 | Borough |
| Plumville | 38 | 246 | 251 | -0.4% | 496 | 0 | Borough |
| Armagh | 39 | 98 | 101 | -1.01% | 1,719 | 0 | Borough |
| Shelocta | 40 | 98 | 101 | -1.01% | 942 | 0 | Borough |
| Smicksburg | 41 | 53 | 55 | -1.85% | 363 | 0 | Borough |
Robinson is the largest city in Indiana County, with a population of 15,847.
Smicksburg is the smallest city in Indiana County, with a population of 53.
There are 41 cities in Indiana County, Pennsylvania.