The site known as Trincheras de Sierra Gorda (Trenches of Sierra Gorda) is located near the Sierra Gorda mountain range in the province of Zaragoza, Spain. The name indicates a system of trenches or field fortifications. Given the location and terminology, these fortifications are most likely associated with the Spanish Civil War (1936-1939), a conflict marked by extensive use of trench warfare and defensive lines across the Spanish countryside.
The specific historical details, construction date, and precise military unit responsible for these particular trenches are not confirmed in the available sources. Further local archaeological or historical research would be required to establish definitive details about their role, period of use, and condition.