Although the designation also includes a portion of the Guareña River's course to the west, and the Zapardiel River's course to the east, the Trabancos River ZEPA SPA designated area is the largest in the Autonomous Community of Castile and León, since it covers almost 1,400 square kilometres, including the Campo de Peñaranda (in Salamanca), the Moraña (in Ávila) and, especially, a large part of the Tierra de Medina del Campo. In all, 73% of the territory of the Trabancos ZEPA SPA corresponds to the province of Valladolid.