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 |
|---|---|---|---|---|---|---|---|
| Hermitage | 1 | 15,816 | 16,243 | -0.67% | 537 | 29.5 | City |
| Sharon | 2 | 12,707 | 13,129 | -0.83% | 3,369 | 3.8 | City |
| Grove City | 3 | 7,747 | 7,875 | -0.41% | 2,874 | 2.7 | Borough |
| Greenville | 4 | 5,467 | 5,534 | -0.31% | 2,897 | 1.9 | Borough |
| Pine township | 5 | 4,692 | 4,794 | -0.76% | 185 | 25.4 | Township |
| Farrell | 6 | 4,129 | 4,253 | -0.74% | 1,824 | 2.3 | City |
| Sharpsville | 7 | 4,113 | 4,248 | -0.82% | 2,957 | 1.4 | Borough |
| Hempfield township | 8 | 3,624 | 3,727 | -0.74% | 256 | 14.2 | Township |
| Shenango township | 9 | 3,410 | 3,516 | -0.93% | 114 | 30.0 | Township |
| West Salem township | 10 | 3,152 | 3,213 | -0.94% | 85 | 36.9 | Township |
| Pymatuning township | 11 | 2,999 | 3,111 | -1.02% | 186 | 16.2 | Township |
| Findley township | 12 | 2,830 | 2,845 | 6.79% | 133 | 21.2 | Township |
| South Pymatuning township | 13 | 2,573 | 2,650 | -0.81% | 131 | 19.6 | Township |
| Lackawannock township | 14 | 2,466 | 2,478 | 0.12% | 118 | 20.9 | Township |
| Delaware township | 15 | 2,049 | 2,086 | -0.63% | 63 | 32.7 | Township |
| Mercer | 16 | 1,916 | 1,982 | -0.88% | 1,656 | 1.2 | Borough |
| East Lackawannock township | 17 | 1,642 | 1,670 | -0.55% | 77 | 21.4 | Township |
| Wilmington township | 18 | 1,415 | 1,407 | 0.5% | 108 | 13.1 | Township |
| Perry township | 19 | 1,290 | 1,331 | -0.85% | 72 | 18.0 | Township |
| Sandy Lake township | 20 | 1,179 | 1,196 | -0.42% | 48 | 24.4 | Township |
| Greene township | 21 | 1,027 | 1,053 | -0.77% | 47 | 21.8 | Township |
| Mercer township | 22 | 1,003 | 1,008 | -0.6% | 77 | 13.0 | Township |
| Stoneboro | 23 | 925 | 948 | -0.64% | 326 | 2.8 | Borough |
| West Middlesex | 24 | 787 | 815 | -0.88% | 931 | 0.8 | Borough |
| Sandy Lake | 25 | 628 | 648 | -0.79% | 755 | 0.8 | Borough |
| Jamestown | 26 | 566 | 581 | -0.7% | 679 | 0.8 | Borough |
| Wheatland | 27 | 564 | 582 | -0.88% | 646 | 0.9 | Borough |
| Clark | 28 | 557 | 575 | -0.89% | 185 | 3.0 | Borough |
| Fredonia | 29 | 422 | 434 | -0.71% | 1,182 | 0.4 | Borough |
| Jackson Center | 30 | 185 | 192 | -1.07% | 163 | 1.1 | Borough |
| New Lebanon | 31 | 185 | 185 | 0% | 145 | 1.3 | Borough |
| Sheakleyville | 32 | 144 | 150 | -1.37% | 735 | 0.2 | 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.
Hermitage is the largest city in Mercer County.
Sheakleyville is the smallest city in Mercer County.
There are 32 cities in Mercer County, Pennsylvania.