Embalse Ezequiel Ramos Mexía, also known as the El Chocón Reservoir, is a massive hydroelectric impoundment on the Limay River in Neuquén Province, Patagonia, Argentina. Created by the El Chocón Dam — a 94-meter-high loose-material dam completed between 1969 and 1977 — the reservoir spans approximately 816 square kilometers (roughly 83,000 hectares) and sits at an elevation of 328 meters above sea level. With a total storage capacity of around 20,155 million cubic meters and a maximum water depth of 60 to 64 meters, it ranks among the largest reservoirs in Argentina. The reservoir is classified as an oligo-mesotrophic water body, meaning it is relatively nutrient-poor and supports clear, cold water conditions typical of Patagonian impoundments. The surrounding landscape is characteristic of northern Patagonian steppe — open, windswept terrain with dramatic geology that gives the reservoir its rugged, expansive character. The dam is currently operated under a concession by BML Inversora S.A.U. (MSU Argentina) running from 2025 to 2055, and the reservoir continues to serve hydroelectric, flood regulation, and irrigation purposes.