| 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 |
| McKean County | 45 936 | 47 131 | - 1 195 | - 2.5 |
| Annin township | 835 | 805 | 30 | 3.7 |
| Bradford city | 9 175 | 9 625 | - 450 | - 4.7 |
| Bradford township | 4 816 | 5 065 | - 249 | - 4.9 |
| Ceres township | 1 003 | 981 | 22 | 2.2 |
| Corydon township | 301 | 319 | - 18 | - 5.6 |
| Eldred borough | 858 | 869 | - 11 | - 1.3 |
| Eldred township | 1 696 | 1 768 | - 72 | - 4.1 |
| Foster township | 4 566 | 4 691 | - 125 | - 2.7 |
| Hamilton township | 637 | 612 | 25 | 4.1 |
| Hamlin township | 819 | 822 | - 3 | - 0.4 |
| Kane borough | 4 126 | 4 590 | - 464 | - 10.1 |
| Keating township | 3 087 | 3 070 | 17 | 0.6 |
| Lafayette township | 2 337 | 2 106 | 231 | 11.0 |
| Lewis Run borough | 577 | 578 | - 1 | - 0.2 |
| Liberty township | 1 726 | 1 764 | - 38 | - 2.2 |
| Mount Jewett borough | 1 070 | 1 029 | 41 | 4.0 |
| Norwich township | 633 | 593 | 40 | 6.7 |
| Otto township | 1 738 | 1 820 | - 82 | - 4.5 |
| Port Allegany borough | 2 355 | 2 391 | - 36 | - 1.5 |
| Sergeant township | 176 | 154 | 22 | 14.3 |
| Smethport borough | 1 684 | 1 734 | - 50 | - 2.9 |
| Wetmore township | 1 721 | 1 745 | - 24 | - 1.4 |
| Source: U.S. Census Bureau | Prepared by: Pennsylvania State Data Center | |||