The Barranco del Río Dulce natural park is a natural park, a Special Conservation Area, a Special Protection Area for Birds and a Site of Community Importance included in the Natura 2000 Network, located in the north of the Spanish province of Guadalajara.

It covers the territory of the municipalities of Algora, Mandayona, Mirabueno, Saúca, Sigüenza and Torremocha del Campo.

It has a total area of 8347 hectares. Its minimum altitude is 888 meters and the maximum is 1,174 meters, with an average of 1,075 meters above sea level.

The Dulce ravine is the result of the erosion of this river on the Iberian erosion surface that forms the high Alcarreño páramo, which is mainly based on Mesozoic limestone and dolomites, with Paleogene outcrops.

During the Cretaceous period, the area was frequently covered by seas, which deposited the current limestone. More recently, in the Quaternary, the river has been dissolving the limestone and excavating the current canyon, originating a wonderful relief, of high moors cut out by the Dulce river canyon and its tributaries, with karst formations such as limestone, caves, chasms, torcas, or tobaceous buildings.

It is a valley that, depending on the lithology, is open and allows the existence of a small cultivated plain or is very closed, with steep slopes and numerous scarps.