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 |
|---|---|---|---|---|---|---|---|
| Philadelphia | 1 | 1,533,828 | 1,600,684 | -1.08% | 11,416 | 134.4 | City |
| Upper Darby township | 2 | 84,894 | 85,573 | 0% | 10,849 | 7.8 | Township |
| Chester | 3 | 33,933 | 32,580 | 1.01% | 7,021 | 4.8 | City |
| Radnor township | 4 | 33,765 | 33,210 | 0.1% | 2,452 | 13.8 | Township |
| Ridley township | 5 | 30,715 | 30,931 | 0.03% | 6,005 | 5.1 | Township |
| Springfield township | 6 | 24,868 | 25,044 | 0.01% | 3,934 | 6.3 | Township |
| Marple township | 7 | 24,114 | 24,200 | 0.13% | 2,364 | 10.2 | Township |
| Springfield township | 8 | 20,962 | 20,805 | -0.1% | 3,115 | 6.7 | Township |
| Upper Chichester township | 9 | 16,789 | 16,880 | 0.05% | 2,510 | 6.7 | Township |
| Aston township | 10 | 16,620 | 16,783 | 0.01% | 2,845 | 5.8 | Township |
| Nether Providence township | 11 | 14,483 | 14,497 | 0.15% | 3,072 | 4.7 | Township |
| Yeadon | 12 | 12,318 | 12,034 | 0.58% | 7,723 | 1.6 | Borough |
| Lansdowne | 13 | 11,070 | 11,096 | -0.06% | 9,373 | 1.2 | Borough |
| Upper Providence township | 14 | 10,792 | 10,858 | 0.06% | 1,927 | 5.6 | Township |
| Darby | 15 | 10,585 | 10,700 | -0.27% | 12,571 | 0.8 | Borough |
| Darby township | 16 | 9,135 | 9,210 | -0.02% | 6,451 | 1.4 | Township |
| Collingdale | 17 | 8,813 | 8,892 | -0.23% | 10,142 | 0.9 | Borough |
| Brookhaven | 18 | 8,291 | 8,291 | 0% | 4,854 | 1.7 | Borough |
| Ridley Park | 19 | 7,199 | 7,265 | -0.24% | 6,672 | 1.1 | Borough |
| Glenolden | 20 | 7,150 | 7,220 | -0.25% | 7,333 | 1.0 | Borough |
| Thornbury township | 21 | 6,910 | 6,895 | 0% | 748 | 9.2 | Township |
| Clifton Heights | 22 | 6,777 | 6,851 | -0.28% | 10,757 | 0.6 | Borough |
| Folcroft | 23 | 6,716 | 6,790 | -0.28% | 5,394 | 1.2 | Borough |
| Swarthmore | 24 | 6,534 | 6,540 | -0.03% | 4,667 | 1.4 | Borough |
| Prospect Park | 25 | 6,357 | 6,425 | -0.27% | 8,684 | 0.7 | Borough |
| Springfield township | 26 | 6,107 | 6,025 | 0.48% | 232 | 26.4 | Township |
| Sharon Hill | 27 | 5,942 | 6,006 | -0.27% | 7,697 | 0.8 | Borough |
| Norwood | 28 | 5,874 | 5,937 | -0.27% | 7,550 | 0.8 | Borough |
| Media | 29 | 5,852 | 5,890 | -0.17% | 7,670 | 0.8 | Borough |
| Wayne township | 30 | 5,340 | 5,209 | 0.58% | 152 | 35.2 | Township |
| Springfield township | 31 | 5,192 | 5,166 | 0.27% | 170 | 30.6 | Township |
| Edgmont township | 32 | 4,752 | 4,293 | 3.17% | 490 | 9.7 | Township |
| Aldan | 33 | 4,198 | 4,245 | -0.29% | 7,032 | 0.6 | Borough |
| Chester township | 34 | 4,029 | 4,067 | -0.03% | 2,821 | 1.4 | Township |
| Tinicum township | 35 | 3,960 | 3,980 | 0.05% | 689 | 5.8 | Township |
| Chadds Ford township | 36 | 3,945 | 3,969 | 0.1% | 456 | 8.7 | Township |
| Lower Chichester township | 37 | 3,374 | 3,403 | -0.03% | 3,144 | 1.1 | Township |
| Upland | 38 | 3,027 | 3,061 | -0.3% | 4,664 | 0.6 | Borough |
| Springfield township | 39 | 2,996 | 3,073 | -0.63% | 80 | 37.4 | Township |
| Chester Heights | 40 | 2,917 | 2,921 | -0.03% | 1,318 | 2.2 | Borough |
| Morton | 41 | 2,750 | 2,774 | -0.22% | 7,682 | 0.4 | Borough |
| East Lansdowne | 42 | 2,679 | 2,710 | -0.3% | 13,005 | 0.2 | Borough |
| Springfield township | 43 | 2,606 | 2,727 | -1.1% | 44 | 59.2 | Township |
| Colwyn | 44 | 2,441 | 2,469 | -0.29% | 9,461 | 0.3 | Borough |
| Eddystone | 45 | 2,428 | 2,456 | -0.29% | 2,440 | 1.0 | Borough |
| Marcus Hook | 46 | 2,425 | 2,452 | -0.29% | 2,189 | 1.1 | Borough |
| Wayne township | 47 | 2,409 | 2,461 | -0.37% | 149 | 16.1 | Township |
| Wayne township | 48 | 2,352 | 2,360 | 0.04% | 48 | 48.7 | Township |
| Parkside | 49 | 2,297 | 2,321 | -0.26% | 11,150 | 0.2 | Borough |
| Trainer | 50 | 1,954 | 1,978 | -0.31% | 1,849 | 1.1 | Borough |
| Springfield township | 51 | 1,815 | 1,852 | -0.98% | 66 | 27.3 | Township |
| Wayne township | 52 | 1,496 | 1,537 | -0.66% | 39 | 38.0 | Township |
| Wayne township | 53 | 1,434 | 1,450 | -0.49% | 64 | 22.3 | Township |
| Wayne township | 54 | 1,402 | 1,407 | -0.07% | 40 | 35.1 | Township |
| Wayne township | 55 | 1,274 | 1,264 | 0.16% | 92 | 13.9 | Township |
| Wayne township | 56 | 1,262 | 1,295 | -0.55% | 28 | 44.7 | Township |
| Millbourne | 57 | 1,198 | 1,213 | -0.33% | 16,189 | 0.1 | Borough |
| Springfield township | 58 | 1,126 | 1,147 | -0.44% | 27 | 41.3 | Township |
| Wayne township | 59 | 1,010 | 1,025 | -0.2% | 26 | 39.2 | Township |
| Rose Valley | 60 | 1,009 | 1,019 | -0.3% | 1,378 | 0.7 | Borough |
| Rutledge | 61 | 776 | 783 | -0.26% | 5,427 | 0.1 | 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.
Philadelphia is the largest city in Delaware County.
Rutledge is the smallest city in Delaware County.
There are 61 cities in Delaware County, Pennsylvania.