| Population Change 1990-2000 | ||||
| County or Municipality | 2000 Population | 1990 Population | Population Change | Percent Change |
| Pennsylvania | 12 281 054 | 11 881 643 | 399 411 | 3.4 |
| Blair County | 129 144 | 130 542 | - 1 398 | - 1.1 |
| Allegheny township | 6 965 | 7 023 | - 58 | - 0.8 |
| Altoona city | 49 523 | 51 881 | - 2 358 | - 4.5 |
| Antis township | 6 328 | 6 176 | 152 | 2.5 |
| Bellwood borough | 2 016 | 1 976 | 40 | 2.0 |
| Blair township | 4 587 | 3 994 | 593 | 14.8 |
| Catharine township | 758 | 738 | 20 | 2.7 |
| Duncansville borough | 1 238 | 1 309 | - 71 | - 5.4 |
| Frankstown township | 7 694 | 7 243 | 451 | 6.2 |
| Freedom township | 3 261 | 2 959 | 302 | 10.2 |
| Greenfield township | 3 904 | 3 802 | 102 | 2.7 |
| Hollidaysburg borough | 5 368 | 5 624 | - 256 | - 4.6 |
| Huston township | 1 262 | 1 189 | 73 | 6.1 |
| Juniata township | 1 115 | 1 116 | - 1 | - 0.1 |
| Logan township | 11 925 | 12 381 | - 456 | - 3.7 |
| Martinsburg borough | 2 236 | 2 119 | 117 | 5.5 |
| Newry borough | 245 | 288 | - 43 | - 14.9 |
| North Woodbury township | 2 276 | 2 219 | 57 | 2.6 |
| Roaring Spring borough | 2 418 | 2 615 | - 197 | - 7.5 |
| Snyder township | 3 358 | 3 163 | 195 | 6.2 |
| Taylor township | 2 239 | 2 327 | - 88 | - 3.8 |
| Tunnelhill borough | 118 | 106 | 12 | 11.3 |
| Tyrone borough | 5 528 | 5 743 | - 215 | - 3.7 |
| Tyrone township | 1 800 | 1 677 | 123 | 7.3 |
| Williamsburg borough | 1 345 | 1 456 | - 111 | - 7.6 |
| Woodbury township | 1 637 | 1 418 | 219 | 15.4 |
| Source: U.S. Census Bureau | Prepared by: Pennsylvania State Data Center | |||