The Yacyretá Dam or Hydroelectric Power Plant Jasyretâ-Apipé (from Guaraní jasy retâ, “country of the moon”) is a dam and hydroelectric power plant built over the waterfalls of Jasyretâ-Apipé in the Paraná River, between the Argentine Province of Corrientes and the Paraguayan department of Misiones. The dam is named for Yacyretâ Island just upstream, much of which the dam submerged. The word “Yacyreta” is a misspelling of the original word, the Guaraní term Jasyretâ.

The dam is 808 meters long, and its installed equipment has a maximum power output of 4,050 MW, with an annual maximum power output of 19,080 GWh, and a maximum water flow rate of 55,000 cubic meters per second. However, because its reservoir is seven meters below its planned water level, the dam currently operates at only 60% capacity.

The project generated controversy and criticism during its planning and construction because of the effects it had on local ecology, particularly the flooding of a unique environment causing the extinction of numerous species. The financial management of the project also garnered criticism, as it greatly exceeded its original budget, ultimately costing more than $11 billion, and earning it a reputation as a "monument to corruption".

In addition to the dam, which is 808 meters long, a barrage of materials 65 kilometers long closes both arms of the river divided by the island Jasyretâ; the hydroelectric dam is in part located over this. Both extremes are settled in the Argentine coast, in the locality of Rincón Santa María and in the Paraguayan coast, near the city of San Cosme y Damián. The artificial lake formed by the dam rises 21 meters above the original level and covers 1600 square kilometers.

Each branch has a slope. The turbines are in the main branch, in a slope with eighteen gates that allow a maximum flow of 55,000 cubic meters per second. The other branch of the river has sixteen more gates with a capacity for another 40,000 cubic meters per second.

A ship lock excavated in the basaltic layer allows passage of boats with draft up to 12 feet (3.6 m). A fish ladder, designed after the ecological studies proved that the presence of the dam inhibited the reproduction of certain migratory species of the Paraná River, especially the dorado and surubí, allows fish that swim upstream to cover the 25-meter difference to spawn in the Alto Paraná.

The machine house is 70 meters high. The waterfall, currently 15 meters high, has an average volume of 8,000 cubic meters per second that pass through the turbines and produce energy continuously. For comparison, the falls of Iguazú are 70 meters high, with a volume of 1,750 cubic meters per second.