| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Portland | 1 | 20,919 | 20,414 | 0.41% | 1,719 | 12 | City |
| Ingleside | 2 | 10,214 | 9,619 | 1.28% | 604 | 17 | City |
| Aransas Pass | 3 | 8,941 | 8,355 | 1.12% | 677 | 13 | City |
| Sinton | 4 | 5,995 | 5,527 | 0.49% | 1,173 | 5 | City |
| Mathis | 5 | 4,311 | 4,327 | -0.02% | 1,300 | 3 | City |
| Taft | 6 | 2,972 | 2,800 | 1.12% | 1,781 | 2 | City |
| Odem | 7 | 2,301 | 2,264 | 0.44% | 1,806 | 1 | City |
| Gregory | 8 | 1,704 | 1,737 | -0.23% | 1,117 | 2 | City |
| Ingleside on the Bay | 9 | 602 | 610 | -0.33% | 2,062 | 0 | City |
Portland is the largest city in San Patricio County, with a population of 20,919.
Ingleside on the Bay is the smallest city in San Patricio County, with a population of 602.
There are 9 cities in San Patricio County, Texas.