81 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Peters | 1 | 23,219 | 22,953 | -0.12% | 1,191 | 20 | Township |
| North Strabane | 2 | 17,381 | 15,767 | 1.68% | 638 | 27 | Township |
| Washington | 3 | 15,414 | 14,869 | 0.02% | 394 | 39 | Township |
| Cecil | 4 | 15,157 | 14,656 | 0.26% | 575 | 26 | Township |
| Amity | 5 | 13,667 | 13,358 | 0.74% | 756 | 18 | Township |
| Washington | 6 | 13,382 | 13,142 | 0.36% | 4,569 | 3 | City |
| South Strabane | 7 | 9,589 | 9,652 | -0.22% | 417 | 23 | Township |
| Canonsburg | 8 | 9,563 | 9,752 | -0.4% | 4,140 | 2 | Borough |
| Chartiers | 9 | 9,296 | 8,681 | 0.66% | 378 | 25 | Township |
| Lawrence | 10 | 7,298 | 7,494 | -0.35% | 88 | 83 | Township |
| Washington | 11 | 6,816 | 6,878 | 0.07% | 213 | 32 | Township |
| Washington | 12 | 6,754 | 6,542 | 1.08% | 287 | 24 | Township |
| Union | 13 | 5,566 | 5,387 | 1.35% | 364 | 15 | Township |
| Carroll | 14 | 5,278 | 5,380 | -0.42% | 392 | 13 | Township |
| Washington | 15 | 5,214 | 5,148 | 0.46% | 292 | 18 | Township |
| North Franklin | 16 | 4,724 | 4,821 | -0.46% | 644 | 7 | Township |
| Washington | 17 | 4,605 | 4,462 | 0.74% | 327 | 14 | Township |
| Donora | 18 | 4,461 | 4,563 | -0.47% | 2,349 | 2 | Borough |
| California | 19 | 4,444 | 5,363 | -3.98% | 404 | 11 | Borough |
| Washington | 20 | 4,381 | 4,390 | 0.02% | 97 | 45 | Township |
| Smith | 21 | 4,202 | 4,233 | -0.05% | 122 | 34 | Township |
| Charleroi | 22 | 4,140 | 4,235 | -0.46% | 5,433 | 1 | Borough |
| Monongahela | 23 | 4,053 | 4,147 | -0.47% | 2,119 | 2 | City |
| Fallowfield | 24 | 4,007 | 4,099 | -0.4% | 188 | 21 | Township |
| Washington | 25 | 3,657 | 3,879 | -1% | 368 | 10 | Township |
| Amwell | 26 | 3,653 | 3,679 | -0.05% | 82 | 45 | Township |
| Washington | 27 | 3,165 | 3,128 | 0.35% | 102 | 31 | Township |
| South Franklin | 28 | 2,832 | 2,874 | -0.28% | 138 | 21 | Township |
| Washington | 29 | 2,670 | 2,581 | 1.21% | 95 | 28 | Township |
| Bentleyville | 30 | 2,327 | 2,365 | -0.34% | 630 | 4 | Borough |
| Hickory | 31 | 2,278 | 2,319 | -0.31% | 144 | 16 | Township |
| East Bethlehem | 32 | 2,246 | 2,296 | -0.53% | 443 | 5 | Township |
| Washington | 33 | 2,137 | 2,130 | 0.23% | 121 | 18 | Township |
| New Eagle | 34 | 2,009 | 2,054 | -0.45% | 1,977 | 1 | Borough |
| Buffalo | 35 | 1,950 | 1,980 | -0.1% | 96 | 20 | Township |
| Washington | 36 | 1,838 | 1,861 | -0.16% | 56 | 33 | Township |
| Washington | 37 | 1,838 | 1,892 | -0.59% | 39 | 48 | Township |
| East Washington | 38 | 1,813 | 1,852 | -0.44% | 4,038 | 0 | Borough |
| Washington | 39 | 1,776 | 1,767 | 0.79% | 37 | 48 | Township |
| Washington | 40 | 1,773 | 1,750 | 0.06% | 74 | 24 | Township |
| Washington | 41 | 1,645 | 1,647 | 0.06% | 43 | 38 | Township |
| Lawrence | 42 | 1,608 | 1,611 | 0.06% | 47 | 34 | Township |
| North Bethlehem | 43 | 1,544 | 1,563 | -0.13% | 70 | 22 | Township |
| West Pike Run | 44 | 1,510 | 1,544 | -0.46% | 93 | 16 | Township |
| Independence | 45 | 1,487 | 1,510 | -0.47% | 58 | 26 | Township |
| Burgettstown | 46 | 1,394 | 1,426 | -0.5% | 2,241 | 1 | Borough |
| Monongahela | 47 | 1,392 | 1,481 | -1.56% | 80 | 17 | Township |
| Cross Creek | 48 | 1,355 | 1,373 | -0.44% | 49 | 28 | Township |
| Washington | 49 | 1,300 | 1,336 | -0.69% | 69 | 19 | Township |
| East Finley | 50 | 1,281 | 1,288 | 0.23% | 36 | 35 | Township |
| North Charleroi | 51 | 1,273 | 1,303 | -0.47% | 4,953 | 0 | Borough |
| West Bethlehem | 52 | 1,266 | 1,291 | -0.47% | 56 | 22 | Township |
| Washington | 53 | 1,241 | 1,287 | -0.64% | 50 | 25 | Township |
| Houston | 54 | 1,145 | 1,172 | -0.52% | 2,786 | 0 | Borough |
| Amity | 55 | 979 | 982 | 0.2% | 35 | 28 | Township |
| Midway | 56 | 911 | 923 | -0.33% | 2,070 | 0 | Borough |
| Ellsworth | 57 | 897 | 919 | -0.55% | 1,214 | 1 | Borough |
| Washington | 58 | 876 | 926 | -1.13% | 32 | 27 | Township |
| Washington | 59 | 865 | 844 | 0% | 65 | 13 | Township |
| Washington | 60 | 861 | 894 | -0.58% | 38 | 22 | Township |
| West Finley | 61 | 833 | 810 | 0.36% | 21 | 39 | Township |
| Washington | 62 | 765 | 750 | 0.53% | 42 | 18 | Township |
| Claysville | 63 | 715 | 730 | -0.42% | 2,314 | 0 | Borough |
| Roscoe | 64 | 699 | 717 | -0.57% | 3,841 | 0 | Borough |
| Washington | 65 | 695 | 710 | 0.14% | 43 | 16 | Township |
| Blaine | 66 | 611 | 620 | -0.49% | 51 | 12 | Township |
| Cokeburg | 67 | 606 | 620 | -0.49% | 1,722 | 0 | Borough |
| Allenport | 68 | 471 | 484 | -0.63% | 221 | 2 | Borough |
| Stockdale | 69 | 414 | 423 | -0.48% | 1,605 | 0 | Borough |
| Long Branch | 70 | 411 | 420 | -0.48% | 129 | 3 | Borough |
| Marianna | 71 | 386 | 396 | -0.52% | 197 | 2 | Borough |
| Hickory | 72 | 384 | 412 | -2.29% | 10 | 38 | Township |
| Beallsville | 73 | 384 | 393 | -0.52% | 158 | 2 | Borough |
| Finleyville | 74 | 366 | 374 | -0.54% | 2,192 | 0 | Borough |
| Dunlevy | 75 | 365 | 370 | -0.27% | 686 | 1 | Borough |
| Daisytown | 76 | 282 | 291 | -0.7% | 1,210 | 0 | Borough |
| Elco | 77 | 255 | 263 | -0.78% | 914 | 0 | Borough |
| Twilight | 78 | 220 | 225 | -0.45% | 137 | 2 | Borough |
| West Middletown | 79 | 108 | 108 | 0% | 266 | 0 | Borough |
| Coal Center | 80 | 106 | 108 | -0.93% | 930 | 0 | Borough |
| Green Hills | 81 | 19 | 19 | 0% | 21 | 1 | Borough |
Peters is the largest city in Washington County, with a population of 23,219.
Green Hills is the smallest city in Washington County, with a population of 19.
There are 81 cities in Washington County, Pennsylvania.