| 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 |
| Perry County | 43 602 | 41 172 | 2 430 | 5.9 |
| Blain borough | 252 | 266 | - 14 | - 5.3 |
| Bloomfield borough | 1 077 | 1 092 | - 15 | - 1.4 |
| Buffalo township | 1 128 | 1 080 | 48 | 4.4 |
| Carroll township | 5 095 | 4 597 | 498 | 10.8 |
| Centre township | 2 209 | 1 974 | 235 | 11.9 |
| Duncannon borough | 1 508 | 1 450 | 58 | 4.0 |
| Greenwood township | 1 010 | 943 | 67 | 7.1 |
| Howe township | 493 | 459 | 34 | 7.4 |
| Jackson township | 525 | 489 | 36 | 7.4 |
| Juniata township | 1 359 | 1 278 | 81 | 6.3 |
| Landisburg borough | 195 | 178 | 17 | 9.6 |
| Liverpool borough | 876 | 934 | - 58 | - 6.2 |
| Liverpool township | 966 | 915 | 51 | 5.6 |
| Marysville borough | 2 306 | 2 425 | - 119 | - 4.9 |
| Miller township | 953 | 894 | 59 | 6.6 |
| Millerstown borough | 679 | 646 | 33 | 5.1 |
| New Buffalo borough | 123 | 145 | - 22 | - 15.2 |
| Newport borough | 1 506 | 1 568 | - 62 | - 4.0 |
| Northeast Madison township | 856 | 674 | 182 | 27.0 |
| Oliver township | 2 061 | 2 039 | 22 | 1.1 |
| Penn township | 3 013 | 3 283 | - 270 | - 8.2 |
| Rye township | 2 327 | 2 136 | 191 | 8.9 |
| Saville township | 2 204 | 1 818 | 386 | 21.2 |
| Southwest Madison township | 856 | 745 | 111 | 14.9 |
| Spring township | 2 021 | 1 665 | 356 | 21.4 |
| Toboyne township | 494 | 455 | 39 | 8.6 |
| Tuscarora township | 1 122 | 1 034 | 88 | 8.5 |
| Tyrone township | 1 863 | 1 741 | 122 | 7.0 |
| Watts township | 1 196 | 1 152 | 44 | 3.8 |
| Wheatfield township | 3 329 | 3 097 | 232 | 7.5 |
| Source: U.S. Census Bureau | Prepared by: Pennsylvania State Data Center | |||