| 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 |
| Lancaster County | 470 658 | 422 822 | 47 836 | 11.3 |
| Adamstown borough | 1 201 | 1 108 | 93 | 8.4 |
| Akron borough | 4 046 | 3 869 | 177 | 4.6 |
| Bart township | 3 003 | 2 774 | 229 | 8.3 |
| Brecknock township | 6 699 | 5 197 | 1 502 | 28.9 |
| Caernarvon township | 4 278 | 3 946 | 332 | 8.4 |
| Christiana borough | 1 124 | 1 045 | 79 | 7.6 |
| Clay township | 5 173 | 5 050 | 123 | 2.4 |
| Colerain township | 3 261 | 2 867 | 394 | 13.7 |
| Columbia borough | 10 311 | 10 701 | - 390 | - 3.6 |
| Conestoga township | 3 749 | 3 470 | 279 | 8.0 |
| Conoy township | 3 067 | 2 687 | 380 | 14.1 |
| Denver borough | 3 332 | 2 861 | 471 | 16.5 |
| Drumore township | 2 243 | 2 114 | 129 | 6.1 |
| Earl township | 6 183 | 5 515 | 668 | 12.1 |
| East Cocalico township | 9 954 | 7 809 | 2 145 | 27.5 |
| East Donegal township | 5 405 | 4 484 | 921 | 20.5 |
| East Drumore township | 3 535 | 3 225 | 310 | 9.6 |
| East Earl township | 5 723 | 5 491 | 232 | 4.2 |
| East Hempfield township | 21 399 | 18 597 | 2 802 | 15.1 |
| East Lampeter township | 13 556 | 11 999 | 1 557 | 13.0 |
| East Petersburg borough | 4 450 | 4 197 | 253 | 6.0 |
| Eden township | 1 856 | 1 857 | - 1 | - 0.1 |
| Elizabeth township | 3 833 | 3 691 | 142 | 3.8 |
| Elizabethtown borough | 11 887 | 9 952 | 1 935 | 19.4 |
| Ephrata borough | 13 213 | 12 133 | 1 080 | 8.9 |
| Ephrata township | 8 026 | 7 116 | 910 | 12.8 |
| Fulton township | 2 826 | 2 688 | 138 | 5.1 |
| Lancaster city | 56 348 | 55 551 | 797 | 1.4 |
| Lancaster township | 13 944 | 13 187 | 757 | 5.7 |
| Leacock township | 4 878 | 4 668 | 210 | 4.5 |
| Lititz borough | 9 029 | 8 280 | 749 | 9.0 |
| Little Britain township | 3 514 | 2 701 | 813 | 30.1 |
| Manheim borough | 4 784 | 5 011 | - 227 | - 4.5 |
| Manheim township | 33 697 | 28 880 | 4 817 | 16.7 |
| Manor township | 16 498 | 14 130 | 2 368 | 16.8 |
| Marietta borough | 2 689 | 2 778 | - 89 | - 3.2 |
| Martic township | 4 990 | 4 362 | 628 | 14.4 |
| Millersville borough | 7 774 | 8 099 | - 325 | - 4.0 |
| Mount Joy borough | 6 765 | 6 398 | 367 | 5.7 |
| Mount Joy township | 7 944 | 6 227 | 1 717 | 27.6 |
| Mountville borough | 2 444 | 1 977 | 467 | 23.6 |
| New Holland borough | 5 092 | 4 484 | 608 | 13.6 |
| Paradise township | 4 698 | 4 430 | 268 | 6.0 |
| Penn township | 7 312 | 6 760 | 552 | 8.2 |
| Pequea township | 4 358 | 4 512 | - 154 | - 3.4 |
| Providence township | 6 651 | 6 071 | 580 | 9.6 |
| Quarryville borough | 1 994 | 1 642 | 352 | 21.4 |
| Rapho township | 8 578 | 8 211 | 367 | 4.5 |
| Sadsbury township | 3 025 | 2 712 | 313 | 11.5 |
| Salisbury township | 10 012 | 8 527 | 1 485 | 17.4 |
| Strasburg borough | 2 800 | 2 568 | 232 | 9.0 |
| Strasburg township | 4 021 | 3 688 | 333 | 9.0 |
| Terre Hill borough | 1 237 | 1 282 | - 45 | - 3.5 |
| Upper Leacock township | 8 229 | 7 254 | 975 | 13.4 |
| Warwick township | 15 475 | 11 622 | 3 853 | 33.2 |
| West Cocalico township | 6 967 | 5 521 | 1 446 | 26.2 |
| West Donegal township | 6 539 | 5 605 | 934 | 16.7 |
| West Earl township | 6 766 | 6 434 | 332 | 5.2 |
| West Hempfield township | 15 128 | 12 942 | 2 186 | 16.9 |
| West Lampeter township | 13 145 | 9 865 | 3 280 | 33.2 |
| Source: U.S. Census Bureau | Prepared by: Pennsylvania State Data Center | |||