| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Sanford | 1 | 68,775 | 61,207 | 1.91% | 2,833 | 24 | City |
| Altamonte Springs | 2 | 48,159 | 46,171 | 0.33% | 5,281 | 9 | City |
| Oviedo | 3 | 41,678 | 39,974 | 0.87% | 2,683 | 16 | City |
| Winter Springs | 4 | 39,843 | 38,394 | 0.65% | 2,681 | 15 | City |
| Casselberry | 5 | 32,470 | 29,076 | 1.88% | 4,659 | 7 | City |
| Longwood | 6 | 17,275 | 15,421 | 2.27% | 3,128 | 6 | City |
| Lake Mary | 7 | 16,783 | 16,834 | -0.04% | 1,849 | 9 | City |
Sanford is the largest city in Seminole County, with a population of 68,775.
Lake Mary is the smallest city in Seminole County, with a population of 16,783.
There are 7 cities in Seminole County, Florida.