Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)
City | Rank | 2024 Pop. | 2020 Pop. | Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Clarion | 1 | 4,418 | 3,926 | 2.86% | 2,807 | 1.6 | Borough |
| Clarion township | 2 | 3,549 | 3,641 | -0.78% | 114 | 31.3 | Township |
| Limestone township | 3 | 1,949 | 1,967 | -0.1% | 58 | 33.6 | Township |
| Limestone township | 4 | 1,812 | 1,869 | -0.88% | 48 | 37.8 | Township |
| Limestone township | 5 | 1,738 | 1,745 | -0.29% | 85 | 20.5 | Township |
| Paint township | 6 | 1,601 | 1,643 | -0.8% | 79 | 20.3 | Township |
| Monroe township | 7 | 1,471 | 1,494 | -0.27% | 50 | 29.4 | Township |
| Elk township | 8 | 1,388 | 1,432 | -0.86% | 44 | 31.5 | Township |
| Redbank township | 9 | 1,294 | 1,327 | -0.54% | 43 | 30.1 | Township |
| Porter township | 10 | 1,240 | 1,284 | -1.04% | 28 | 43.9 | Township |
| Knox | 11 | 1,069 | 1,097 | -0.65% | 1,902 | 0.6 | Borough |
| New Bethlehem | 12 | 945 | 975 | -0.84% | 2,028 | 0.5 | Borough |
| Rimersburg | 13 | 911 | 941 | -0.87% | 2,503 | 0.4 | Borough |
| East Brady | 14 | 798 | 818 | -0.62% | 986 | 0.8 | Borough |
| Sligo | 15 | 669 | 685 | -0.59% | 475 | 1.4 | Borough |
| Strattanville | 16 | 520 | 538 | -0.95% | 1,040 | 0.5 | Borough |
| Hawthorn | 17 | 465 | 477 | -0.64% | 454 | 1.0 | Borough |
| Shippenville | 18 | 434 | 442 | -0.46% | 1,119 | 0.4 | Borough |
| St. Petersburg | 19 | 329 | 339 | -0.9% | 1,031 | 0.3 | Borough |
| Foxburg | 20 | 177 | 180 | -0.56% | 481 | 0.4 | Borough |
| Callensburg | 21 | 143 | 147 | -0.69% | 986 | 0.1 | Borough |
Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.
Clarion is the largest city in Clarion County.
Callensburg is the smallest city in Clarion County.
There are 21 cities in Clarion County, Pennsylvania.