9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Gulfport | 1 | 72,791 | 72,871 | -0.02% | 1,309 | 55.62 | City |
| Biloxi | 2 | 47,445 | 49,420 | -0.83% | 1,105 | 42.94 | City |
| Long Beach | 3 | 17,114 | 16,806 | 0.36% | 1,671 | 10.24 | City |
| D'Iberville | 4 | 13,667 | 12,714 | 1.42% | 1,294 | 10.56 | City |
| St. Martin | 5 | 7,871 | 8,211 | 0.11% | 1,835 | 4.29 | CDP |
| Pass Christian | 6 | 6,594 | 5,746 | 2.65% | 801 | 8.24 | City |
| Latimer | 7 | 6,525 | 6,148 | 0.45% | 401 | 16.28 | CDP |
| Lyman | 8 | 1,481 | 2,303 | 0.95% | 191 | 7.77 | CDP |
| Saucier | 9 | 1,163 | 1,245 | -1.02% | 168 | 6.94 | CDP |
Gulfport is the largest city in Harrison County, with a population of 72,791.
Saucier is the smallest city in Harrison County.
There are 9 cities in Harrison County, Mississippi.