Castro de Rei, is a municipality in the province of Lugo, in the autonomous community of Galicia, Spain.

The Minho runs through the municipality and derives secondary manifolds, which are Azúmara, the Lea, and Anllo.

The region is characterized by its plains and its vast wetlands, home to waterfowl and large communities of amphibians.

Associated with these wetlands appears a landscape mosaic, ecologically rich with color and an ample variety of habitats: grasslands, crops, forests, heath and rushes.

The functional organization of the territory follows a monocentric structure with three main comarcas: Vilalba, Guitiriz and Castro de Rei.