Almonacid de la Cuba Dam
Location	Zaragoza province, Aragon, Spain
Coordinates	41°16′29″N 0°47′20″W / 41.2748°N 0.7890°W / 41.2748; -0.7890
Opening date	1st century
Dam and spillways
Impounds	Aguasvivas (Ebro basin)
Height	34 m (112 ft)
Length	120 m (390 ft)
Width (base)	38 m (125 ft)

The Almonacid de la Cuba Dam is a Roman gravity dam on the Aguasvivas River in Almonacid de la Cuba, Zaragoza province, Aragon, Spain, dating to the 1st century AD.^[1] This dam, with a height of 34 metres (112 ft) was the highest in the Spain until 1590.^[2]

Construction was begun under Augustus; the remains of this earlier, three-arched, dam on the site have been detected, but it was breached by flooding early, perhaps even during construction. Immediately thereafter it was reconstructed as a gravity dam, incorporating portions of the earlier structure. It underwent repairs under Claudius and under Trajan, at which time it was heightened, probably to offset the effects of silting.^[1]

The dam was abandoned by the Moors in the 13th century, but later reused, and is still in use today.^[3] In 2020 a system of walkways and footbridges was constructed to allow visitors a close-up view of the dam and its surroundings.^[4] In 2024 the town of Almonacid de la Cuba was spared by the dam from flooding that devastated other nearby towns.^[3]

• List of Roman dams and reservoirs
• Roman architecture
• Roman engineering

• Arenillas, Miguel; Castillo, Juan C. (2003), "Dams from the Roman Era in Spain. Analysis of Design Forms (with Appendix)", 1st International Congress on Construction History [20th–24th January], Madrid, retrieved 29 December 2018 – via TRAIANVS

• Arenillas, Miguel (2002), La presa romana de Almonacid de la Cuba, archived from the original on 25 December 2009, retrieved 24 October 2009

• Roman dam Almonacid de la Cuba (in Spanish)