Magusto, Magosto, Magosta, Castanyada, or Festa da castanha is a traditional festival in the Iberian Peninsula. It is popular in Portugal, Galicia and some areas of northern Spain, such as Cantabria, Asturias, Catalonia, and the provinces of León, Zamora and Salamanca and Cáceres, but also in some parts of the Canary Islands. The festival is also celebrated in both sides of the French-Spanish border. It has also spread internationally as a 'chestnut party'. Etymological origins are unknown, but there are several theories for the Magosto name: Magnus Ustus (great fire) or Magum Ustum (highlighting the magical character of fire).
It is believed to have Celtic roots, similar to the Samhain festival that celebrates the end of summer and the beginning of winter. In all the regions where it is celebrated, and especially in Galicia and Portugal, it is deeply related to the cult of the dead. It is customary to leave the fire of the house lit and place food around the fireplace to welcome back the spirits deceased members of the family. Numerous traditional rituals are celebrated throughout this feast related to purification, healing, remembering ancestors, attending mass or visiting the local healer.