34 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Clarion | 1 | 4,248 | 3,926 | 1.29% | 2,699 | 2 | Borough |
| Clarion | 2 | 3,538 | 3,641 | -0.45% | 113 | 31 | Township |
| Limestone | 3 | 1,960 | 1,967 | 0% | 58 | 34 | Township |
| Limestone | 4 | 1,817 | 1,870 | -0.33% | 48 | 38 | Township |
| Limestone | 5 | 1,724 | 1,748 | -0.58% | 84 | 21 | Township |
| Paint | 6 | 1,610 | 1,646 | -0.31% | 79 | 20 | Township |
| Monroe | 7 | 1,481 | 1,492 | 0% | 50 | 29 | Township |
| Elk | 8 | 1,388 | 1,431 | -0.36% | 44 | 31 | Township |
| Redbank | 9 | 1,291 | 1,328 | -0.39% | 43 | 30 | Township |
| Porter | 10 | 1,245 | 1,285 | -0.4% | 28 | 44 | Township |
| Knox | 11 | 1,062 | 1,097 | -0.56% | 1,890 | 1 | Borough |
| Limestone | 12 | 1,009 | 1,012 | 0% | 76 | 13 | Township |
| Knox | 13 | 985 | 992 | 0.31% | 61 | 16 | Township |
| Knox | 14 | 969 | 1,010 | -0.72% | 31 | 31 | Township |
| Toby | 15 | 956 | 981 | -0.31% | 33 | 29 | Township |
| New Bethlehem | 16 | 943 | 975 | -0.53% | 2,024 | 0 | Borough |
| Rimersburg | 17 | 918 | 950 | -0.54% | 2,522 | 0 | Borough |
| Perry | 18 | 894 | 920 | -0.33% | 31 | 29 | Township |
| Salem | 19 | 879 | 898 | -0.34% | 55 | 16 | Township |
| East Brady | 20 | 797 | 818 | -0.38% | 985 | 1 | Borough |
| Sligo | 21 | 666 | 680 | -0.3% | 473 | 1 | Borough |
| Licking | 22 | 574 | 573 | 0% | 33 | 18 | Township |
| Knox | 23 | 574 | 596 | -0.52% | 22 | 26 | Township |
| Highland | 24 | 531 | 532 | -0.38% | 27 | 20 | Township |
| Strattanville | 25 | 517 | 538 | -0.58% | 1,034 | 1 | Borough |
| Hawthorn | 26 | 464 | 479 | -0.43% | 453 | 1 | Borough |
| Shippenville | 27 | 442 | 444 | 0% | 1,139 | 0 | Borough |
| Piney | 28 | 398 | 401 | 0.25% | 22 | 18 | Township |
| Millcreek | 29 | 370 | 361 | 1.09% | 13 | 29 | Township |
| St. Petersburg | 30 | 326 | 337 | -0.61% | 1,022 | 0 | Borough |
| Limestone | 31 | 291 | 310 | -1.36% | 9 | 31 | Township |
| Foxburg | 32 | 179 | 182 | 0% | 486 | 0 | Borough |
| Callensburg | 33 | 138 | 146 | -0.72% | 952 | 0 | Borough |
| Brady | 34 | 71 | 75 | -1.39% | 43 | 2 | Township |
Clarion is the largest city in Clarion County, with a population of 4,248.
Brady is the smallest city in Clarion County, with a population of 71.
There are 34 cities in Clarion County, Pennsylvania.