Casas del Castañar is a municipality in the province of Cáceres, in the Extremadura region of western Spain. It lies near the Sierra de Gredos mountain range, which rises to the north and east of the area.
The village sits in the foothills of the Sierra de Gredos, a granite range that separates the northern part of the province of Cáceres from the provinces of Ávila and Salamanca. The surrounding terrain is mountainous, and the municipality forms part of the rural, sparsely populated north of Extremadura.
Like other settlements in the province of Cáceres, Casas del Castañar is administered as a municipality, the basic unit of local government in Spain. Its position near the Sierra de Gredos places it within one of the most prominent natural areas of the region.