Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)
City | Rank | 2024 Pop. | 2020 Pop. | Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Peters township | 1 | 23,268 | 22,958 | 0.02% | 1,193 | 19.5 | Township |
| North Strabane township | 2 | 17,142 | 15,690 | 2.53% | 629 | 27.3 | Township |
| Washington township | 3 | 15,611 | 14,867 | 1.41% | 400 | 39.1 | Township |
| Cecil township | 4 | 15,201 | 14,651 | 0.9% | 577 | 26.4 | Township |
| Washington | 5 | 13,518 | 13,162 | 0.66% | 4,615 | 2.9 | City |
| Amity township | 6 | 13,444 | 13,392 | 0.19% | 744 | 18.1 | Township |
| Canonsburg | 7 | 9,589 | 9,748 | -0.41% | 4,151 | 2.3 | Borough |
| South Strabane township | 8 | 9,580 | 9,640 | -0.33% | 417 | 23.0 | Township |
| Chartiers township | 9 | 9,195 | 8,679 | 0.29% | 374 | 24.6 | Township |
| Lawrence township | 10 | 7,286 | 7,500 | -0.83% | 88 | 82.5 | Township |
| Washington township | 11 | 6,776 | 6,878 | -0.34% | 212 | 32.0 | Township |
| Washington township | 12 | 6,558 | 6,544 | -0.01% | 278 | 23.6 | Township |
| Union township | 13 | 5,471 | 5,384 | 1.02% | 358 | 15.3 | Township |
| Carroll township | 14 | 5,296 | 5,380 | -0.36% | 393 | 13.5 | Township |
| Washington township | 15 | 5,153 | 5,145 | 0.04% | 289 | 17.8 | Township |
| North Franklin township | 16 | 4,750 | 4,824 | -0.36% | 648 | 7.3 | Township |
| Washington township | 17 | 4,531 | 4,464 | 0.22% | 322 | 14.1 | Township |
| Donora | 18 | 4,479 | 4,561 | -0.47% | 2,359 | 1.9 | Borough |
| California | 19 | 4,398 | 5,361 | -5.2% | 399 | 11.0 | Borough |
| Washington township | 20 | 4,359 | 4,392 | -0.37% | 96 | 45.2 | Township |
| Smith township | 21 | 4,183 | 4,233 | -0.36% | 121 | 34.5 | Township |
| Charleroi | 22 | 4,153 | 4,235 | -0.5% | 5,450 | 0.8 | Borough |
| Monongahela | 23 | 4,067 | 4,147 | -0.49% | 2,126 | 1.9 | City |
| Fallowfield township | 24 | 4,021 | 4,100 | -0.42% | 189 | 21.3 | Township |
| Washington township | 25 | 3,660 | 3,888 | -1.48% | 369 | 9.9 | Township |
| Amwell township | 26 | 3,646 | 3,682 | -0.3% | 81 | 44.8 | Township |
| Washington township | 27 | 3,146 | 3,124 | 0.26% | 101 | 31.0 | Township |
| South Franklin township | 28 | 2,828 | 2,871 | -0.35% | 137 | 20.6 | Township |
| Washington township | 29 | 2,609 | 2,579 | 0.35% | 93 | 28.0 | Township |
| Bentleyville | 30 | 2,323 | 2,355 | -0.34% | 629 | 3.7 | Borough |
| Hickory township | 31 | 2,286 | 2,316 | -0.04% | 144 | 15.8 | Township |
| East Bethlehem township | 32 | 2,278 | 2,312 | -0.35% | 450 | 5.1 | Township |
| Washington township | 33 | 2,104 | 2,130 | -0.47% | 119 | 17.7 | Township |
| New Eagle | 34 | 2,013 | 2,057 | -0.54% | 1,981 | 1.0 | Borough |
| Buffalo township | 35 | 1,952 | 1,983 | -0.26% | 96 | 20.4 | Township |
| Washington township | 36 | 1,851 | 1,892 | -0.27% | 39 | 47.6 | Township |
| Washington township | 37 | 1,826 | 1,863 | -0.71% | 55 | 32.9 | Township |
| East Washington | 38 | 1,817 | 1,851 | -0.49% | 4,047 | 0.4 | Borough |
| Washington township | 39 | 1,792 | 1,753 | 1.19% | 75 | 23.9 | Township |
| Washington township | 40 | 1,736 | 1,768 | -0.46% | 36 | 48.2 | Township |
| Washington township | 41 | 1,647 | 1,648 | 0.18% | 43 | 38.1 | Township |
| Lawrence township | 42 | 1,596 | 1,611 | -0.31% | 46 | 34.5 | Township |
| North Bethlehem township | 43 | 1,527 | 1,551 | -0.39% | 69 | 22.1 | Township |
| West Pike Run township | 44 | 1,515 | 1,543 | -0.39% | 93 | 16.3 | Township |
| Independence township | 45 | 1,494 | 1,510 | -0.2% | 58 | 25.8 | Township |
| Monongahela township | 46 | 1,432 | 1,485 | -0.42% | 82 | 17.4 | Township |
| Burgettstown | 47 | 1,395 | 1,425 | -0.57% | 2,243 | 0.6 | Borough |
| Cross Creek township | 48 | 1,370 | 1,373 | 0.29% | 50 | 27.5 | Township |
| Washington township | 49 | 1,307 | 1,336 | -0.83% | 69 | 18.9 | Township |
| East Finley township | 50 | 1,278 | 1,288 | 0.16% | 36 | 35.1 | Township |
| North Charleroi | 51 | 1,275 | 1,302 | -0.55% | 4,961 | 0.3 | Borough |
| West Bethlehem township | 52 | 1,267 | 1,291 | -0.55% | 57 | 22.4 | Township |
| Washington township | 53 | 1,248 | 1,286 | -0.48% | 50 | 24.9 | Township |
| Houston | 54 | 1,146 | 1,169 | -0.52% | 2,788 | 0.4 | Borough |
| Ellsworth | 55 | 920 | 940 | -0.54% | 1,245 | 0.7 | Borough |
| Midway | 56 | 912 | 923 | -0.33% | 2,073 | 0.4 | Borough |
| Claysville | 57 | 715 | 729 | -0.56% | 2,314 | 0.3 | Borough |
| Roscoe | 58 | 703 | 719 | -0.57% | 3,863 | 0.2 | Borough |
| Cokeburg | 59 | 614 | 626 | -0.49% | 1,744 | 0.4 | Borough |
| Allenport | 60 | 475 | 485 | -0.63% | 223 | 2.1 | Borough |
| Stockdale | 61 | 416 | 424 | -0.48% | 1,612 | 0.3 | Borough |
| Long Branch | 62 | 412 | 420 | -0.48% | 129 | 3.2 | Borough |
| Beallsville | 63 | 386 | 393 | -0.52% | 159 | 2.4 | Borough |
| Marianna | 64 | 386 | 396 | -0.77% | 197 | 2.0 | Borough |
| Finleyville | 65 | 369 | 376 | -0.54% | 2,210 | 0.2 | Borough |
| Dunlevy | 66 | 362 | 369 | -0.55% | 680 | 0.5 | Borough |
| Daisytown | 67 | 283 | 291 | -0.7% | 1,215 | 0.2 | Borough |
| Elco | 68 | 258 | 264 | -0.77% | 925 | 0.3 | Borough |
| Twilight | 69 | 212 | 216 | -0.47% | 132 | 1.6 | Borough |
| Coal Center | 70 | 110 | 110 | 0% | 965 | 0.1 | Borough |
| West Middletown | 71 | 109 | 109 | 0% | 268 | 0.4 | Borough |
| Green Hills | 72 | 20 | 20 | 0% | 22 | 0.9 | Borough |
Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.
Peters township is the largest city in Washington County.
Green Hills is the smallest city in Washington County.
There are 72 cities in Washington County, Pennsylvania.