Sant Miquel de Castelló, Romanesque church in La Vall d'en Bas, Spain.

Sant Miquel de Castelló is a single-nave Romanesque chapel with a barrel vault and no separate apse, its present state dating from a 1947 restoration. It stands on a buttress of the Serrat de Sant Miquel above the Hostalets d'en Bas, built of small, barely dressed stones set in lime mortar in regular courses. The only feature identifying it as a church is a single-opening bell gable above the roof.

The church was the chapel of the castle of the viscounts of Bas. The fortress is documented from the 11th century, but the church itself appears only once, in late 14th-century diocesan lists as "Capella Sancti Michaelis de Castilione in parrochia sancti Stephani de Occulo". The building was restored in 1947 and since 1974 has served as a mountain refuge for 20 people run by the GEIEG.

The name comes from the dedication to Saint Michael, recorded in late 14th-century diocesan lists as "Capella Sancti Michaelis de Castilione in parrochia sancti Stephani de Occulo". Since 1974 the former chapel has been used as a mountain refuge with 20 places, run by the GEIEG hiking club.

The site is located in a mountainous area and is best reached on foot via hiking trails through the Vall d'en Bas. The terrain can be rough, so suitable footwear is necessary.

Since 1974 the chapel has served as a mountain refuge with space for 20 people, run by the Girona hiking club GEIEG. The building keeps a single nave under a barrel vault, and its present look comes from a restoration carried out in 1947.