Castro of Santa Trega is an archaeological site located on the hillsides of Mount Santa Trega, in the southwestern Galician municipality of A Guarda, Spain. The site is strategically located overlooking the mouth of the river Miño, at 341 meters (1118 feet) above sea level. Belonging to the Castro culture, it's one of the most emblematic and visited Galician forts (castros).

In 1931, it was declared a National Historical and Artistic Monument (‘Monumento Histórico Artístico Nacional’) and was also considered a Place of Cultural Interest (‘Bien de Interés Cultural’: BIC).