| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Lebanon | 1 | 26,393 | 26,756 | -0.32% | 6,334 | 4 | City |
| Richland | 2 | 14,342 | 13,834 | 0.22% | 694 | 21 | Township |
| North Lebanon | 3 | 12,477 | 12,058 | 0.9% | 745 | 17 | Township |
| Richland | 4 | 11,873 | 11,935 | 0.28% | 811 | 15 | Township |
| Richland | 5 | 11,869 | 12,241 | -0.56% | 574 | 21 | Township |
| South Lebanon | 6 | 10,820 | 10,425 | 0.79% | 499 | 22 | Township |
| North Cornwall | 7 | 9,839 | 8,502 | 1.84% | 1,036 | 9 | Township |
| North Londonderry | 8 | 9,185 | 8,912 | 0.83% | 855 | 11 | Township |
| South Londonderry | 9 | 8,958 | 8,782 | 0.2% | 368 | 24 | Township |
| Palmyra | 10 | 7,740 | 7,825 | -0.28% | 4,025 | 2 | Borough |
| Swatara | 11 | 5,094 | 5,057 | 0.41% | 236 | 22 | Township |
| Annville | 12 | 5,068 | 4,760 | 0.62% | 3,125 | 2 | Township |
| Cornwall | 13 | 4,713 | 4,599 | 0.32% | 486 | 10 | Borough |
| Millcreek | 14 | 4,479 | 4,347 | 0.81% | 219 | 20 | Township |
| Heidelberg | 15 | 4,224 | 4,133 | 1.29% | 174 | 24 | Township |
| South Annville | 16 | 3,548 | 3,438 | 0.88% | 182 | 19 | Township |
| Palmyra | 17 | 3,408 | 3,217 | 0.5% | 100 | 34 | Township |
| Myerstown | 18 | 3,165 | 3,099 | 0.25% | 3,697 | 1 | Borough |
| Union | 19 | 2,940 | 2,936 | 0.27% | 99 | 30 | Township |
| East Hanover | 20 | 2,736 | 2,659 | 0.77% | 84 | 32 | Township |
| North Annville | 21 | 2,342 | 2,278 | 0.77% | 136 | 17 | Township |
| West Cornwall | 22 | 2,088 | 2,027 | 0.77% | 242 | 9 | Township |
| Cleona | 23 | 2,061 | 2,014 | 0.29% | 2,471 | 1 | Borough |
| Jonestown | 24 | 1,671 | 1,630 | 0.3% | 2,636 | 1 | Borough |
| Richland | 25 | 1,528 | 1,493 | 0.26% | 1,103 | 1 | Borough |
| Palmyra | 26 | 1,259 | 1,244 | 0.16% | 79 | 16 | Township |
| Richland | 27 | 757 | 773 | -0.53% | 34 | 22 | Township |
| Lebanon | 28 | 723 | 681 | 1.54% | 19 | 37 | Township |
| Richland | 29 | 472 | 467 | -0.42% | 31 | 15 | Township |
| Mount Gretna | 30 | 193 | 189 | 0% | 1,340 | 0 | Borough |
| Cold Spring | 31 | 61 | 58 | 1.67% | 2.0 | 25 | Township |
Lebanon is the largest city in Lebanon County, with a population of 26,393.
Cold Spring is the smallest city in Lebanon County, with a population of 61.
There are 31 cities in Lebanon County, Pennsylvania.