Castellnou de Carcolze is a medieval fortress in Alt Urgell, Catalonia, documented from 964 onwards and mentioned in connection with the 839 parish, with the castle first formally recorded as sold by viscount Guillem d'Urgell in 996. Situated at 1,380 meters altitude, it once served as a strategic outpost of the Counts of Cerdanya before entering decline in the late 12th century. Today, scant remains of a rudimentary rectangular enclosure survive, alongside the adjacent Gothic Church of Sant Girvés featuring a single nave, representing the sparse yet enduring evidence of this frontier settlement.
