Lake Nicaragua or Cocibolca or Granada (Spanish: Lago de Nicaragua, Lago Cocibolca, Mar Dulce, Gran Lago, Gran Lago Dulce, or Lago de Granada) is a freshwater lake in Nicaragua. Of tectonic origin and with an area of 8,264 km² (3,191 sq mi), it is the largest lake in Central America, the 19th largest lake in the world (by area) and the tenth largest in the Americas, slightly smaller than Lake Titicaca. With an elevation of 32.7 metres (107 ft) above sea level, the lake reaches a depth of 26 metres (85 ft). It is intermittently joined by the Tipitapa River to Lake Managua.

The lake drains to the Caribbean Sea via the San Juan River, historically making the lakeside city of Granada an Atlantic port, although Granada (as well as the entire lake) is closer to the Pacific Ocean geographically. The Pacific is near enough to be seen from the mountains of Ometepe (an island in the lake). The lake has a history of Caribbean pirates who assaulted Granada on three occasions. Before construction of the Panama Canal, a stagecoach line owned by Cornelius Vanderbilt's Accessory Transit Company connected the lake with the Pacific across the low hills of the narrow Isthmus of Rivas. Plans were made to take advantage of this route to build an interoceanic canal, the Nicaragua Canal, but the Panama Canal was built instead. In order to quell competition with the Panama Canal, the U.S. secured all rights to a canal along this route in the Bryan–Chamorro Treaty of 1916. However, since this treaty was mutually rescinded by the United States and Nicaragua in 1970, the idea of another canal in Nicaragua still periodically resurfaced, such as the Ecocanal proposal. In 2014, the government of Nicaragua offered a 50-year concession to the Hong Kong Nicaragua Canal Development Investment Company (HKND) to build a canal across Nicaragua at a cost of US$40 billion, with construction beginning in December 2014 and completing in 2019. Protests against the ecological and social effects of the canal as well as questions about financing have led to doubts about the project.