9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Port St. Lucie | 1 | 270,491 | 206,815 | 4.94% | 2,269 | 119.22 | City |
| Fort Pierce | 2 | 50,550 | 47,610 | 1.18% | 2,093 | 24.16 | City |
| Lakewood Park | 3 | 14,818 | 14,227 | 1.6% | 2,223 | 6.67 | CDP |
| Indian River Estates | 4 | 7,151 | 6,542 | 0.87% | 1,288 | 5.55 | CDP |
| Fort Pierce North | 5 | 6,530 | 7,199 | 0.06% | 1,542 | 4.24 | CDP |
| River Park | 6 | 6,427 | 7,139 | 1.26% | 2,733 | 2.35 | CDP |
| White City | 7 | 5,938 | 5,091 | 2.56% | 1,193 | 4.98 | CDP |
| Fort Pierce South | 8 | 5,377 | 4,468 | 0.39% | 2,074 | 2.59 | CDP |
| St. Lucie Village | 9 | 601 | 610 | -0.33% | 669 | 0.90 | Town |
Port St. Lucie is the largest city in St. Lucie County, with a population of 270,491.
St. Lucie Village is the smallest city in St. Lucie County.
There are 9 cities in St. Lucie County, Florida.