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 |
|---|---|---|---|---|---|---|---|
| Altoona | 1 | 42,418 | 43,898 | -0.86% | 4,332 | 9.8 | City |
| Logan township | 2 | 12,127 | 12,388 | -0.36% | 261 | 46.4 | Township |
| Frankstown township | 3 | 7,603 | 7,400 | 1.56% | 156 | 48.8 | Township |
| Allegheny township | 4 | 6,518 | 6,575 | -0.21% | 220 | 29.6 | Township |
| Antis township | 5 | 6,313 | 6,480 | -0.55% | 104 | 60.8 | Township |
| Hollidaysburg | 6 | 5,462 | 5,638 | -0.8% | 2,344 | 2.3 | Borough |
| Tyrone | 7 | 5,281 | 5,469 | -0.88% | 2,595 | 2.0 | Borough |
| Blair township | 8 | 4,649 | 4,779 | -0.58% | 341 | 13.6 | Township |
| Greenfield township | 9 | 3,676 | 3,782 | -0.54% | 102 | 36.1 | Township |
| Snyder township | 10 | 3,285 | 3,343 | -0.21% | 73 | 45.1 | Township |
| North Woodbury township | 11 | 2,403 | 2,432 | -0.08% | 114 | 21.1 | Township |
| Tyrone township | 12 | 2,334 | 2,269 | 0.91% | 109 | 21.5 | Township |
| Roaring Spring | 13 | 2,294 | 2,378 | -0.91% | 2,850 | 0.8 | Borough |
| Tyrone township | 14 | 1,926 | 1,919 | -0.16% | 54 | 35.7 | Township |
| Tyrone township | 15 | 1,816 | 1,866 | -0.33% | 43 | 41.8 | Township |
| Martinsburg | 16 | 1,814 | 1,877 | -0.87% | 2,808 | 0.6 | Borough |
| Bellwood | 17 | 1,757 | 1,820 | -0.9% | 3,691 | 0.5 | Borough |
| Huston township | 18 | 1,238 | 1,248 | 0% | 35 | 34.9 | Township |
| Duncansville | 19 | 1,205 | 1,249 | -0.91% | 2,265 | 0.5 | Borough |
| Williamsburg | 20 | 1,187 | 1,229 | -0.92% | 3,234 | 0.4 | Borough |
| Tunnelhill | 21 | 307 | 318 | -0.97% | 621 | 0.5 | Borough |
| Newry | 22 | 229 | 237 | -0.87% | 2,337 | 0.1 | Borough |
| Birmingham | 23 | 86 | 89 | -1.15% | 1,365 | 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.
Altoona is the largest city in Blair County.
Birmingham is the smallest city in Blair County.
There are 23 cities in Blair County, Pennsylvania.