Castell de Subirats, Medieval castle in Subirats, Spain.

Castell de Subirats stands at 300 metres on a limestone spur above the Penedès plain, beside the church of Sant Pere del Castell. Of the fortress that once covered the whole summit, part of the eastern wall, the structure called the baluard and part of the main nucleus remain, including the tower of homage probably built in the 11th century.

The castle is documented from 917, when Ermenard and Udalard, sons of the late Udalard, made a grant to the monastery of Sant Cugat del Vallès. In 1060 a testament of Mir Geribert records a donation to Sant Pere de castro Subiradz. In 1368 Peter IV of Aragon gave Subirats to the future Martin I, and in 1377 Ramon Alamany de Cervelló obtained it. The Marquis of los Vélez took and demolished it around 1641 during the Reapers' War.

The ruins stand beside the church of Sant Pere del Castell, also known as the sanctuary of the Mare de Déu de la Fontsanta. The castle and church share the same limestone spur, and the dedication to Saint Peter appears in a 1060 testament by Mir Geribert as "sanctum Petrum de castro Subiradz".

The ruins lie on a narrow limestone spur beside the church of Sant Pere del Castell, reached from the BP-2427 road between Sant Sadurní d'Anoia and Sant Pau d'Ordal via a turn-off north from Els Casots. The terrain is uneven rock, so sturdy footwear helps. A restoration and consolidation project in 2004 covered the keep, the adjoining enclosures, the baluard and the eastern wall.

The castle stands on a limestone spur aligned with the nearby castle of Gelida to the northeast and, further north, the Torre Ramona. In 2004 a restoration and consolidation project covered the keep, its adjoining enclosures, the structure known as the baluard and the eastern wall.