The museum is housed in an old fortress built in the 16th century. From the 16th to the 18th centuries, it was a defensive building and prison, later used as a quarantine station to isolate sailors arriving in the city affected by infectious diseases. The museum as such was inaugurated in 1968. It has been considered a historical-artistic monument since 1949 and a Cultural Interest Site since 1994. The museum houses archaeological objects such as: protohistoric goldsmithing, megalithism, Bronze Age, Castro culture, Romanization, and various aspects of the city. Some of these objects come from the Castro de Elviña. The Castle houses the following facilities:
- Library (Casa Botero)
- Exhibition rooms (ground floor)
- Exhibition rooms, sacristy, and chapel (upper floor)
- Casemates (annexes – ground floor)
- Cistern (annexes)
SCHEDULE: Winter (September to June): Tuesday to Saturday from 10:00 to 19:30. Sundays and holidays from 10:00 to 14:30 (access is not allowed from half an hour before closing). Closed on January 1, Carnival Monday and Tuesday, and December 24, 25, and 31. Summer (July and August): Tuesday to Saturday from 10:00 to 21:00. Sundays and holidays from 10:00 to 15:00 (access is not allowed from half an hour before closing).