| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Hempfield | 1 | 41,245 | 41,533 | -0.42% | 537 | 77 | Township |
| North Huntingdon | 2 | 31,647 | 31,848 | -0.16% | 1,159 | 27 | Township |
| Derry | 3 | 25,162 | 24,770 | -0.07% | 927 | 27 | Township |
| Manor | 4 | 21,940 | 21,837 | -0.13% | 572 | 38 | Township |
| Unity | 5 | 21,120 | 21,585 | -0.36% | 313 | 67 | Township |
| Penn | 6 | 20,836 | 20,113 | 0.39% | 677 | 31 | Township |
| Murrysville | 7 | 20,569 | 20,966 | -0.32% | 558 | 37 | Township |
| Penn | 8 | 18,677 | 17,482 | 0.83% | 1,439 | 13 | Township |
| Greensburg | 9 | 14,370 | 14,912 | -0.64% | 3,551 | 4 | City |
| Derry | 10 | 13,311 | 13,589 | -0.37% | 139 | 96 | Township |
| New Kensington | 11 | 11,684 | 12,129 | -0.64% | 2,959 | 4 | City |
| Rostraver | 12 | 11,475 | 11,381 | 0.17% | 357 | 32 | Township |
| Penn | 13 | 10,865 | 9,976 | 1.61% | 367 | 30 | Township |
| Mount Pleasant | 14 | 9,927 | 10,142 | -0.35% | 179 | 55 | Township |
| Jeannette | 15 | 8,434 | 8,759 | -0.65% | 3,532 | 2 | City |
| Allegheny | 16 | 8,099 | 8,314 | -0.43% | 261 | 31 | Township |
| Latrobe | 17 | 7,781 | 8,048 | -0.58% | 3,360 | 2 | Borough |
| East Huntingdon | 18 | 7,573 | 7,694 | -0.18% | 230 | 33 | Township |
| Derry | 19 | 7,254 | 7,220 | 0.14% | 236 | 31 | Township |
| Penn | 20 | 6,635 | 5,643 | 4.65% | 691 | 10 | Township |
| Monessen | 21 | 6,614 | 6,863 | -0.65% | 2,291 | 3 | City |
| Salem | 22 | 5,985 | 6,142 | -0.35% | 127 | 47 | Township |
| Ligonier | 23 | 5,939 | 6,061 | -0.22% | 64 | 92 | Township |
| South Huntingdon | 24 | 5,282 | 5,422 | -0.4% | 116 | 45 | Township |
| Penn | 25 | 4,872 | 5,017 | -0.37% | 201 | 24 | Township |
| Vandergrift | 26 | 4,870 | 5,062 | -0.67% | 3,578 | 1 | Borough |
| Mount Pleasant | 27 | 4,818 | 4,669 | 0.44% | 159 | 30 | Township |
| Scottdale | 28 | 4,244 | 4,404 | -0.63% | 3,643 | 1 | Borough |
| Mount Pleasant | 29 | 4,081 | 4,239 | -0.66% | 4,077 | 1 | Borough |
| Penn | 30 | 4,065 | 4,048 | -0.81% | 231 | 18 | Township |
| Manor | 31 | 4,059 | 4,194 | -0.22% | 245 | 17 | Township |
| Irwin | 32 | 3,736 | 3,874 | -0.61% | 4,464 | 1 | Borough |
| Manor | 33 | 3,464 | 3,574 | -0.52% | 1,811 | 2 | Borough |
| Mount Pleasant | 34 | 3,358 | 3,299 | 0.21% | 94 | 36 | Township |
| Penn | 35 | 3,201 | 3,099 | 0.69% | 151 | 21 | Township |
| Trafford | 36 | 3,189 | 3,316 | -0.69% | 2,205 | 1 | Borough |
| Penn | 37 | 2,947 | 2,874 | 0.34% | 100 | 30 | Township |
| Youngwood | 38 | 2,861 | 2,959 | -0.59% | 1,492 | 2 | Borough |
| Delmont | 39 | 2,631 | 2,607 | 0.04% | 2,491 | 1 | Borough |
| West Newton | 40 | 2,551 | 2,654 | -0.7% | 2,460 | 1 | Borough |
| Derry | 41 | 2,544 | 2,643 | -0.66% | 3,295 | 1 | Borough |
| Madison | 42 | 2,527 | 2,471 | 0.52% | 149 | 17 | Township |
| Donegal | 43 | 2,370 | 2,411 | -0.38% | 57 | 41 | Township |
| New Stanton | 44 | 2,331 | 2,312 | -0.3% | 582 | 4 | Borough |
| Penn | 45 | 2,312 | 2,151 | 0.22% | 125 | 18 | Township |
| Donegal | 46 | 2,189 | 2,194 | 0.09% | 45 | 49 | Township |
| Southwest Greensburg | 47 | 2,132 | 2,218 | -0.7% | 5,439 | 0 | Borough |
| Upper Burrell | 48 | 2,105 | 2,161 | -0.43% | 139 | 15 | Township |
| Bell | 49 | 2,076 | 2,086 | -0.24% | 97 | 21 | Township |
| South Greensburg | 50 | 2,064 | 2,120 | -0.43% | 2,919 | 1 | Borough |
| Loyalhanna | 51 | 2,031 | 2,079 | -0.49% | 94 | 22 | Township |
| Cook | 52 | 1,828 | 1,885 | -0.44% | 39 | 47 | Township |
| Donegal | 53 | 1,771 | 1,822 | -0.23% | 76 | 23 | Township |
| Madison | 54 | 1,578 | 1,560 | 0.51% | 45 | 35 | Township |
| Apollo | 55 | 1,523 | 1,598 | -0.91% | 4,993 | 0 | Borough |
| Mount Pleasant | 56 | 1,523 | 1,503 | 0.26% | 91 | 17 | Township |
| Mount Pleasant | 57 | 1,465 | 1,440 | 0.14% | 26 | 56 | Township |
| Ligonier | 58 | 1,452 | 1,509 | -0.68% | 2,881 | 1 | Borough |
| Irwin | 59 | 1,226 | 1,252 | -0.16% | 40 | 30 | Township |
| Penn | 60 | 1,189 | 1,197 | -0.42% | 42 | 28 | Township |
| Penn | 61 | 1,160 | 1,194 | -0.43% | 48 | 24 | Township |
| Madison | 62 | 1,134 | 1,146 | 0.09% | 43 | 27 | Township |
| Penn | 63 | 1,086 | 1,093 | 0.18% | 38 | 29 | Township |
| Derry | 64 | 1,076 | 1,095 | 0.09% | 67 | 16 | Township |
| Penn | 65 | 892 | 892 | -0.45% | 34 | 26 | Township |
| Avonmore | 66 | 868 | 897 | -0.57% | 590 | 1 | Borough |
| Export | 67 | 859 | 892 | -0.69% | 2,132 | 0 | Borough |
| Madison | 68 | 794 | 824 | -0.25% | 26 | 30 | Township |
| Penn | 69 | 654 | 435 | 7.21% | 4,166 | 0 | Borough |
| New Florence | 70 | 643 | 669 | -0.77% | 1,960 | 0 | Borough |
| East Vandergrift | 71 | 569 | 593 | -0.7% | 4,516 | 0 | Borough |
| Sutersville | 72 | 542 | 552 | -0.18% | 1,993 | 0 | Borough |
| Larimer | 73 | 531 | 545 | -0.19% | 32 | 17 | Township |
| Hyde Park | 74 | 487 | 507 | -0.81% | 2,029 | 0 | Borough |
| New Alexandria | 75 | 475 | 494 | -0.84% | 561 | 1 | Borough |
| Bolivar | 76 | 416 | 433 | -0.72% | 2,433 | 0 | Borough |
| Southwest | 77 | 408 | 426 | -0.73% | 12 | 34 | Township |
| Seward | 78 | 392 | 408 | -0.76% | 1,941 | 0 | Borough |
| Madison | 79 | 348 | 360 | -0.57% | 798 | 0 | Borough |
| Smithton | 80 | 331 | 345 | -0.9% | 3,245 | 0 | Borough |
| Hunker | 81 | 300 | 310 | -0.66% | 1,186 | 0 | Borough |
| Arona | 82 | 242 | 253 | -0.82% | 464 | 1 | Borough |
| Youngstown | 83 | 236 | 247 | -0.84% | 2,126 | 0 | Borough |
| Laurel Mountain | 84 | 141 | 146 | -0.7% | 1,093 | 0 | Borough |
| Adamsburg | 85 | 135 | 140 | -0.74% | 482 | 0 | Borough |
| Donegal | 86 | 98 | 102 | -1.01% | 432 | 0 | Borough |
Hempfield is the largest city in Westmoreland County, with a population of 41,245.
Donegal is the smallest city in Westmoreland County, with a population of 98.
There are 86 cities in Westmoreland County, Pennsylvania.