Sarreaus is a municipality in the province of Ourense, within the autonomous community of Galicia in northwestern Spain. It belongs to the comarca (county) of A Limia, a district centred on the town of Xinzo de Limia.
The municipality is located in the southern part of Galicia, in an inland area of the province of Ourense. A Limia is a broad, relatively flat basin, distinct from the more mountainous and coastal terrain found elsewhere in Galicia.
As a Galician municipality, Sarreaus is one of the many small administrative units, or concellos, that make up the region's local government structure. The province of Ourense is one of the four provinces of Galicia, alongside A Coruña, Lugo, and Pontevedra.