Located in Mutriku, on the coastal Route of Santiago, the Church of San Andrés de Astigarribia is a noteworthy building from a monumental and an historic point of view, and is in many ways unique within the landscape of Gipuzkoa. Already cited in documents dating from the 11 th Century, the Church is believed to be one of the oldest in the province of Gipuzkoa due to its pre Romanesque elements.

A study of the monument has revealed that the oldest still preserved sections are from the reconstruction of a prior church. In San Andrés we find a building within a building, with a corridor around the perimeter between them. The interior building has at its head a window in horseshoe arch, which has led to various interpretations, such as that it suggests a Visigoth origin.

This window was part of the original 11 th century Church , no longer standing, and was later used in its current location. The necropolis found at the foot of the current Church also dates to the original structure, a small rural style building, probably partly constructed in wood.