This Gallaecian-Roman settlement was occupied from the 4th century BCE to the 1st century CE during the process of Romanisation in the northwest of the Iberian Peninsula. An excavation was carried out in the eighties, and after that only a 20% of the settlement was open for visitors on the north side of the hilltop. A simple wall surrounds an area measuring 700 m north to south by 300 m east to west that comprises one of the largest castros (hillfort settlements) in Galicia. The design of the wall suggests that its purpose was to define boundaries rather than to defend or deter. It was made of stone masonry with clay and was not more than 160 cm wide. The houses inside are round or oval and for the most part they do not share common walls. There are also a few rectangular huts with rounded corners. They are built directly onto bedrock and their walls are set in mortar made of lime and sand. Some of them have benches attached to the walls on the inside and floors of rammed earth or slabs. On many doorsteps there are pivot-holes for doors. Many artefacts were recovered from the site, including a common element of Gallaecian castros: lots of pottery sherds. They are a mix of native ceramics, made of dark paste by hand or on a slow-wheel, and other fragments from the Roman period, such as green-gloss bell-beaker ware and pieces of red-gloss terra sigillata, as well as sherds of common Roman pottery. Among the recovered objects were many fragments of Roman glass in various shapes and colours, glass beads, bronze necklaces, fragments of bronze bracelets, gaming pieces and objects made of precious metals. Significant finds were uncovered during another excavation carried out by the Provincial Council of Pontevedra between 2015 and 2016, such as a stone head, Roman amphorae and lamps, terra sigillata pottery, fragments of decorated reliefs and more than 42,500 other pieces. Santa Trega is undoubtedly very important in regards to the cultural heritage of the region of Rías Baixas and Galicia