The Castil de Griegos Archaeological Site is an important Celtiberian settlement located near Checa, in the province of Guadalajara, within the Alto Tajo Natural Park. It lies at an altitude of approximately 1,474 meters, in a strategic position between the Serranía de Cuenca and the Sierra de Albarracín. The site dates back to the 5th to 1st centuries BC, with several phases of occupation. The oldest corresponds to an oval enclosure with unmortared walls, and the most recent to an extension with a second fortified enclosure.