Donostialdea
Donostialdea is one of the eight regions of Gipuzkoa, in the Basque Autonomous Community, corresponding to the basin of the lower Urumea River, along with a strip of basin corresponding to the Oria River, the region borrowing its name from Donostia-San Sebastián, the capital city of Gipuzkoa in Spain. The region comprises eleven municipalities extending in an area of 305.72 km2. It borders in the east with the region or subcomarca of Oarsoaldea, on the south with Leitzaldea or Norte de Aralar in Spanish, on the west with Urola Kosta and on the north with the Bay of Biscay.
| # | Municipality | Mayor | Party | Area km² | Population | % Population |
| 1 | Donostia-San Sebastián | Juan Carlos Izagirre | Bildu | 60.89 | 185,510 | 57.0 |
| 2 | Errenteria | Julen Mendoza Pérez | Bildu | 32.26 | 39,010 | 12.0 |
| 3 | Hernani | Luis Intxauspe Arozena | Bildu | 39.82 | 19,317 | 5.9 |
| 4 | Lasarte-Oria | Pablo Barrio Ramírez | Bildu | 6.01 | 17,863 | 5.5 |
| 5 | Pasaia | Amaya Aguirregabiria Alberdi | Bildu | 11.34 | 15,988 | 4.9 |
| 6 | Andoain | Ana Maria Karrere Zabala | Bildu | 27.17 | 14,670 | 4.5 |
| 7 | Oiartzun | Aiora Pérez de San Román | Bildu | 59.71 | 9,957 | 3.1 |
| 8 | Urnieta | Mikel Pagola Tolosa | EAJ/PNV | 22.40 | 6,166 | 1.9 |
| 9 | Lezo | Ainhoa Zabalo Loyarte | Bildu | 8.59 | 6,034 | 1.9 |
| 10 | Usurbil | Mertxe Aizpurua Olano | Bildu | 25.64 | 6,006 | 1.8 |
| 11 | Astigarraga | Andoni Gartzia Arruabarrena | Bildu | 11.89 | 4,714 | 1.4 |
| Donostialdea | 305.72 | 325,235 | 100.0 |
The area is served by the Metro Donostialdea, a service of Euskotren Trena or Basque Railways.