19 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Bel Air South | 1 | 59,459 | 55,024 | 1.33% | 2,795 | 21 | CDP |
| Bel Air North | 2 | 31,493 | 30,639 | 0.2% | 1,972 | 16 | CDP |
| Edgewood | 3 | 25,004 | 25,065 | -0.15% | 1,462 | 17 | CDP |
| Aberdeen | 4 | 18,996 | 16,283 | 2.95% | 2,729 | 7 | City |
| Aberdeen | 5 | 18,996 | 16,270 | 2.95% | 2,729 | 7 | City |
| Havre Grace | 6 | 15,318 | 14,806 | 0.63% | 2,580 | 6 | City |
| Havre Grace | 7 | 15,318 | 14,835 | 0.63% | 2,580 | 6 | City |
| Bel Air | 8 | 10,319 | 10,661 | -0.73% | 3,404 | 3 | Town |
| Bel Air | 9 | 10,319 | 10,698 | -0.73% | 3,404 | 3 | Town |
| Fallston | 10 | 10,201 | 9,118 | 0.82% | 729 | 14 | CDP |
| Abingdon | 11 | 6,389 | 5,324 | 7.14% | 2,313 | 3 | CDP |
| Riverside | 12 | 5,799 | 5,888 | -0.7% | 2,219 | 3 | CDP |
| Pleasant Hills | 13 | 4,062 | 4,017 | 1.15% | 932 | 4 | CDP |
| Aberdeen Proving Ground | 14 | 2,856 | 2,724 | 1.82% | 257 | 11 | CDP |
| Jarrettsville | 15 | 2,617 | 2,827 | -0.76% | 303 | 9 | CDP |
| Perryman | 16 | 2,418 | 2,397 | 0.21% | 444 | 5 | CDP |
| Bel Air | 17 | 1,773 | 1,504 | 1.96% | 2,581 | 1 | CDP |
| Pylesville | 18 | 802 | 1,015 | 1.01% | 169 | 5 | CDP |
| Darlington | 19 | 495 | 522 | 1.02% | 474 | 1 | CDP |
Bel Air South is the largest city in Harford County, with a population of 59,459.
Darlington is the smallest city in Harford County, with a population of 495.
There are 19 cities in Harford County, Maryland.