# Ucero Castle Trail (PRC-SO 66) What to do en Río Lobos Canyon · Río Lobos Canyon Fuente: https://www.geocalia.com/en/spain/castile-and-leon/rio-lobos-canyon/things-to-do/ucero-castle-trail · Revisado: 2026-11-12 - Duración: 2 h - Temporada: All year - Para quién: Families Circular of about 8 km beside the river Ucero, along the old Roman channel of Uxama, to the castle ruins · 2 h · easy An easy loop, with few climbs, that leaves from the Park House, follows the river Ucero from its source, climbs to Ucero castle, crosses through the rock the Roman channel that carried water to Uxama and returns through the village. It is the PRC-SO 66 trail and Patrimonio Natural describes it as suitable for all kinds of people. Its official listing gives it 7.89 km, with altitudes between 953 and 1,023 m; other guides put it at about 6 km. Allow about two hours with stops. The route Leave the Park House heading north. After about 500 m you pass the campsite gate, cross under the SO-920 bridge over the river Ucero and carry on west to the Fuente Engómez car park. From there the trail goes east to the source, where the river Ucero springs, with a small viewpoint; on this stretch you walk about 300 m along the road. Then it continues on the left bank, crosses the Río Chico and climbs south along the steepest stretch of the loop, up to the castle. From the castle you go down about 600 m towards the SO-920 and take the SO-P-5119 road for about 50 m, towards Nafría de Ucero. After about 200 m you turn north towards the entrance to the Roman channel: a 130 m gallery cut into the rock that carried the river's water to Uxama, the Celtiberian and later Roman city beside El Burgo de Osma. Then you enter Ucero, cross the bridge, walk through the village's old vegetable gardens at the foot of the castle crag and return east over another bridge to the Park House. Ucero castle The castle is known from the 13th century, and in 1302 the Bishop of Osma bought the town; since then it passed through various prelates, and in the 15th century Bishop Pedro de Montoya rebuilt it. Today what remain are the walls of the rooms that closed the courtyard, the keep and the cistern. A pointed vault with decorated corbels survives, and a keystone with an agnus dei, which some scholars link to Templar symbolism. From the top you command the valley and the village. Among the ruins, watch where you step and keep children close. Tips Take care on the road sections: the 300 m to the source, the SO-920 crossings and the stretch of the SO-P-5119. In flood season the passage under the SO-920 bridge can be flooded; then cross above. You can go with a dog on a lead. Bring water. If you want more, the Gullurías route leaves from the same car park and climbs to the moorland, and the San Bartolomé hermitage can be reached on foot from Fuente Engómez. ## Cómo llegar y contacto - Coordenadas: 41.7193, -3.0457 ## Cerca de aquí - [Gullurías Trail (PRC-SO 67)](https://www.geocalia.com/en/spain/castile-and-leon/rio-lobos-canyon/things-to-do/gullurias-trail), a 305 m - [Río Lobos Canyon Park House, in Ucero](https://www.geocalia.com/en/spain/castile-and-leon/rio-lobos-canyon/things-to-do/park-house), a 305 m - [El Balcón del Cañón](https://www.geocalia.com/en/spain/castile-and-leon/rio-lobos-canyon/where-to-eat/el-balcon-del-canon), a 309 m - [El Balcón del Cañón](https://www.geocalia.com/en/spain/castile-and-leon/rio-lobos-canyon/where-to-stay/el-balcon-del-canon), a 309 m - [Los Templarios Restaurant](https://www.geocalia.com/en/spain/castile-and-leon/rio-lobos-canyon/where-to-eat/restaurante-los-templarios), a 476 m - [Posada Los Templarios](https://www.geocalia.com/en/spain/castile-and-leon/rio-lobos-canyon/where-to-stay/posada-los-templarios), a 476 m - [Guided Caving in the Galiana Alta Cave](https://www.geocalia.com/en/spain/castile-and-leon/rio-lobos-canyon/things-to-do/caving-in-la-galiana-alta-cave), a 1.5 km - [Río Lobos Trail, along the Canyon Floor](https://www.geocalia.com/en/spain/castile-and-leon/rio-lobos-canyon/things-to-do/rio-lobos-trail), a 3.2 km ## Preguntas frecuentes ### Is it suitable for children? Yes: it is easy with little ascent, though it has road sections and the climb to the castle. ### Where do I park? At the Park House, where the loop starts and ends. Destino: [Río Lobos Canyon](https://www.geocalia.com/en/spain/castile-and-leon/rio-lobos-canyon.md)