39 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Clarion | 1 | 4,541 | 3,926 | 2.78% | 2,885 | 1.57 | Borough |
| Clarion township | 2 | 3,521 | 3,641 | -0.79% | 113 | 31.27 | Township |
| Limestone township | 3 | 1,947 | 1,967 | -0.1% | 58 | 33.62 | Township |
| Limestone township | 4 | 1,796 | 1,869 | -0.88% | 47 | 37.83 | Township |
| Limestone township | 5 | 1,733 | 1,745 | -0.29% | 84 | 20.55 | Township |
| Paint township | 6 | 1,588 | 1,643 | -0.81% | 78 | 20.33 | Township |
| Monroe township | 7 | 1,467 | 1,494 | -0.27% | 50 | 29.45 | Township |
| Elk township | 8 | 1,376 | 1,432 | -0.86% | 44 | 31.46 | Township |
| Redbank township | 9 | 1,287 | 1,327 | -0.54% | 43 | 30.05 | Township |
| Porter township | 10 | 1,227 | 1,284 | -1.05% | 28 | 43.88 | Township |
| Knox | 11 | 1,062 | 1,097 | -0.65% | 1,890 | 0.56 | Borough |
| Marianne | 12 | 1,000 | 1,043 | -1.09% | 690 | 1.45 | CDP |
| Limestone township | 13 | 994 | 1,012 | -0.2% | 74 | 13.35 | Township |
| Knox township | 14 | 987 | 1,007 | -0.1% | 31 | 31.43 | Township |
| Knox township | 15 | 952 | 991 | -0.94% | 59 | 16.02 | Township |
| Toby township | 16 | 943 | 981 | -1.05% | 32 | 29.04 | Township |
| New Bethlehem | 17 | 938 | 975 | -0.74% | 2,013 | 0.47 | Borough |
| Rimersburg | 18 | 904 | 941 | -0.77% | 2,484 | 0.36 | Borough |
| Perry township | 19 | 884 | 921 | -0.9% | 31 | 28.80 | Township |
| Salem township | 20 | 870 | 896 | -0.68% | 54 | 16.04 | Township |
| East Brady | 21 | 793 | 818 | -0.63% | 980 | 0.81 | Borough |
| Sligo | 22 | 665 | 685 | -0.6% | 473 | 1.41 | Borough |
| Licking township | 23 | 580 | 572 | 0.87% | 33 | 17.52 | Township |
| Knox township | 24 | 567 | 597 | -1.22% | 22 | 25.81 | Township |
| Highland township | 25 | 539 | 533 | 0.37% | 27 | 19.91 | Township |
| Strattanville | 26 | 516 | 538 | -0.77% | 1,032 | 0.50 | Borough |
| Hawthorn | 27 | 462 | 477 | -0.65% | 451 | 1.02 | Borough |
| Shippenville | 28 | 432 | 442 | -0.46% | 1,113 | 0.39 | Borough |
| Piney township | 29 | 389 | 401 | -0.51% | 22 | 17.77 | Township |
| Millcreek township | 30 | 352 | 361 | -0.56% | 12 | 28.94 | Township |
| St. Petersburg | 31 | 327 | 339 | -0.61% | 1,025 | 0.32 | Borough |
| Limestone township | 32 | 296 | 310 | -1% | 9 | 31.43 | Township |
| Crown | 33 | 233 | 229 | 1.3% | 92 | 2.54 | CDP |
| Foxburg | 34 | 176 | 180 | -0.56% | 478 | 0.37 | Borough |
| Callensburg | 35 | 142 | 147 | -0.7% | 979 | 0.14 | Borough |
| Vowinckel | 36 | 141 | 68 | 0% | 57 | 2.46 | CDP |
| Leeper | 37 | 132 | 201 | -1.49% | 252 | 0.52 | CDP |
| Tylersburg | 38 | 72 | 99 | -10% | 122 | 0.59 | CDP |
| Brady township | 39 | 71 | 75 | -1.39% | 43 | 1.65 | Township |
Clarion is the largest city in Clarion County, with a population of 4,541.
Brady township is the smallest city in Clarion County.
There are 39 cities in Clarion County, Pennsylvania.