| City | 2026 Pop. ↓ |
|---|---|
| Cordoba | 323,053 |
| Coruna, A | 252,521 |
| Cartagena | 221,697 |
| Castello de la Plana/Castellon de la Plana | 185,937 |
| Cadiz | 108,876 |
| Caceres | 96,818 |
| Cornella de Llobregat | 92,809 |
| Chiclana de la Frontera | 92,059 |
| Ceuta | 83,482 |
| Coslada | 80,331 |
| Ciudad Real | 76,402 |
| Castelldefels | 70,666 |
| Collado Villalba | 67,996 |
| Colmenar Viejo | 60,255 |
| Cerdanyola del Valles | 58,719 |
| Calvia | 54,288 |
| Cuenca | 53,412 |