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 |
|---|---|---|---|---|---|---|---|
| Lebanon | 1 | 26,239 | 26,794 | -0.53% | 6,297 | 4.2 | City |
| Richland township | 2 | 14,291 | 13,826 | 0.81% | 692 | 20.7 | Township |
| North Lebanon township | 3 | 12,146 | 12,049 | 0.33% | 725 | 16.8 | Township |
| Richland township | 4 | 11,930 | 12,232 | -0.51% | 577 | 20.7 | Township |
| Richland township | 5 | 11,652 | 11,929 | -0.71% | 796 | 14.6 | Township |
| South Lebanon township | 6 | 10,613 | 10,423 | 0.56% | 489 | 21.7 | Township |
| North Cornwall township | 7 | 9,725 | 8,509 | 3.1% | 1,024 | 9.5 | Township |
| North Londonderry township | 8 | 8,980 | 8,917 | 0.3% | 836 | 10.7 | Township |
| South Londonderry township | 9 | 8,780 | 8,786 | -0.17% | 361 | 24.4 | Township |
| Palmyra | 10 | 7,662 | 7,821 | -0.52% | 3,984 | 1.9 | Borough |
| Swatara township | 11 | 5,008 | 5,059 | -0.28% | 232 | 21.6 | Township |
| Annville township | 12 | 4,962 | 4,755 | 0.24% | 3,059 | 1.6 | Township |
| Cornwall | 13 | 4,626 | 4,609 | 0.09% | 477 | 9.7 | Borough |
| Millcreek township | 14 | 4,396 | 4,366 | 0.27% | 215 | 20.4 | Township |
| Heidelberg township | 15 | 4,030 | 4,100 | -0.25% | 166 | 24.2 | Township |
| South Annville township | 16 | 3,458 | 3,438 | 0.26% | 178 | 19.5 | Township |
| Palmyra township | 17 | 3,337 | 3,205 | 0.54% | 98 | 34.1 | Township |
| Myerstown | 18 | 3,113 | 3,097 | 0.13% | 3,637 | 0.9 | Borough |
| Union township | 19 | 2,888 | 2,932 | -0.28% | 97 | 29.6 | Township |
| East Hanover township | 20 | 2,678 | 2,657 | 0.3% | 83 | 32.5 | Township |
| North Annville township | 21 | 2,284 | 2,277 | 0.18% | 132 | 17.3 | Township |
| Cleona | 22 | 2,022 | 2,013 | 0.1% | 2,424 | 0.8 | Borough |
| West Cornwall township | 23 | 2,002 | 1,995 | 0.2% | 232 | 8.6 | Township |
| Jonestown | 24 | 1,648 | 1,636 | 0.18% | 2,599 | 0.6 | Borough |
| Richland | 25 | 1,504 | 1,496 | 0.13% | 1,086 | 1.4 | Borough |
| Palmyra township | 26 | 1,254 | 1,242 | 0.24% | 79 | 15.9 | Township |
| Mount Gretna | 27 | 188 | 187 | 0% | 1,306 | 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.
Lebanon is the largest city in Lebanon County.
Mount Gretna is the smallest city in Lebanon County.
There are 27 cities in Lebanon County, Pennsylvania.