| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| San Luis Obispo | 1 | 51,298 | 47,184 | 1.31% | 3,761 | 14 | City |
| El Paso de Robles (Paso Robles) | 2 | 31,634 | 31,488 | 0.03% | 1,588 | 20 | City |
| Atascadero | 3 | 29,437 | 29,746 | -0.09% | 1,129 | 26 | City |
| Arroyo Grande | 4 | 18,070 | 18,437 | -0.29% | 3,043 | 6 | City |
| Grover Beach | 5 | 12,418 | 12,667 | -0.31% | 5,371 | 2 | City |
| Morro Bay | 6 | 10,574 | 10,758 | -0.37% | 1,981 | 5 | City |
| Pismo Beach | 7 | 7,886 | 8,056 | -0.32% | 2,255 | 3 | City |
San Luis Obispo is the largest city in San Luis Obispo County, with a population of 51,298.
Pismo Beach is the smallest city in San Luis Obispo County, with a population of 7,886.
There are 7 cities in San Luis Obispo County, California.