Lake Nicaragua: The Largest Lake in Central America

Lake Nicaragua is the largest lake in Central America. It is also the largest source of freshwater in Nicaragua and it is part of the largest international drainage basin of Central America. Together with Lake Managua and the San Juan River, Lake Nicaragua forms an enormous tectonic valley with a total surface area of 41,000 km2.

Lake Nicaragua Stats

Lake NameLake Nicaragua
Surface area7833.320
Maximum depth26.0
Average depth13.3
Lake typeRift lake
Catchment area25625.40
OutflowsSan Juan River
Islands400 - most important are Granada, Ometepe, Solentiname Islands, and Zapatera
Shore length812.17
SettlementsAltagracia, Granada, Moyogalpa, San Carlos, San Jorge
Residence time4934.9
Trophic stateEutrophic
Average discharge243.917

Lake Nicaragua Accommodation

Geography and Formation

Lake Nicaragua is often referred to as Cocibolca or even Granada after the large city found on its shore. Its current name is said to be derived from “Nicarao”, which was the name of an Indian chief whose tribe lived on the shore of the lake. The name Cocibolca is often used by local Nicaraguans, which also refer to it as “Mar Dulce”, meaning “Sweet Sea” in Spanish.

The lake is the largest in Central America, the 9th largest in the Americas and it is the 19th biggest lake in the World considering its surface area. The lake is connected to its northwestern neighbor, Lake Managua through the Tipitapa River. The two lakes used to be part of an ocean bay, which became an inland basin with two lakes after a volcanic eruption. That is how some ocean fish got stuck in the lake and eventually adapted as the salt sea water gradually turned into freshwater. Nicaragua is the only freshwater lake which has oceanic creatures living in it (such as swordfish, tarpon, and even bull sharks).

The lake has more than 40 tributaries, but only as one outlet, the San Juan River, which, after it exits the at the southeastern part of the lake, flows for more than 180 kilometers through a densely forested region, eventually pouring into the Caribbean Sea. Although the lake lies closer to the Pacific Ocean, the lake’s outflow has made the city of Granada an Atlantic port. At one part of the river’s course it forms the boundary between Nicaragua and Costa Rica. To the southwest the lake is separated from the Pacific Ocean by a narrow land corridor, the 19 kilometer wide Rivas Isthmus.

Sizable waves form on the surface of the lakes, driven by easterly winds, which blow west towards the Pacific Ocean. The water levels are mostly high between May and October and are the lowest between December and April. The water temperature on the surface is 24OC, whilst it is 16OC at the bottom. The lake has a reputation for sudden, powerful and unnavigable storms.

Four main port cities can be found on the shores of the lake: Granada, San Carlos, San Jorge and San Miguelito. Although the area surrounding the lake is densely populated, the transportation system on the lake is still poorly developed.


The lake is home to more than 400 islands, of which 300 are within 8 kilometers of the city of Grenada on the northwestern shore. Most of the islands are covered in exceptionally rich vegetation, which includes tropical fruit trees. One of the largest islands is Ometepe, formed originally of two separate volcanoes, the Concepcion (1610 m, and still alive) and the Madera (1394 m, and dormant). Lava from former eruptions formed a bridge between the two volcanoes, which is today called the Tistian Isthmus. The island is the leading site in Nicaragua of pre-Columbian examples of statues, ceramics and other archaeological remains, some even representing vestiges of ancient South American civilizations. The island is preferred by the more sporty and adventurous types, since you can go volcano hiking, biking, surfing, fishing, kayaking, swimming and visit tropical forests and natural reserves. You can get to Ometepe Island with regular ferry rides starting from Granada and Rivas.

Zapatera is another indigenous sanctuary, containing thousands of artifacts and relics, which are on display in several museums. The island has some small settlements on it, where you can get a glimpse of local rural life.

The Granada islets are a group of 365 islets of different shapes and sizes. They were formed by the volcanic activity of the Mombacho volcano, found on the western shore of the lake, with a height of 1350 meters. A whole community lives on these islands, some having schools and churches on them.

Locals get around by boats. Some islets even have holiday homes and hotels on them, open for any visitor. The best way to experience the islets is to take a boat tour.

The Solentiname Archipelago is a group of 36 islands of volcanic origin, with rich bird and wildlife sanctuaries. The rustic communities living here have created a unique style of primitive art, using bright colors and simple shapes in paintings and handicraft.

Flora and Fauna

The lake serves as a very important factor of the Nicaraguan landscape. It has several types of ecosystems along its shores. The south and southwest are mostly known for their moist tropical forests, whilst the eastern, northern and western part of the lake are mainly covered in tropical dry forests dotted by agricultural lands. The tops of the Maderas and Mombacho volcanoes are home to unique ecosystems; they are the only two places where cloud forests can be found on the Pacific side on the North, with impressive flora and fauna.

A high number of birds make the Lake Nicaragua area even more colorful. Wading birds such as egrets and herons stand on the waterside while cormorants can most often be seen hunting for fish. Some birds of prey like hawks and kites also hunt around Lake Nicaragua. The greatest variety of birds can be found around Ometepe Island at the Rio Istian, around the Solentiname Archipelago and the Granada Islets.

More than 40 fish species live in the lake, of which 16 are cichlids, which make up 58% of the lake’s biomass. Despite being a freshwater lake, sawfish, tarpon and sharks live in Lake Nicaragua. Scientists originally thought that the sharks belonged to an endemic species called the Lake Nicaragua Shark. They affirmed in 1961 after comparison of specimens that the Lake Nicaragua Shark was synonymized with widespread bull shark, a specimen known for entering fresh waters in other parts of the world. One hypothesis proclaimed that the sharks were trapped within the lake. This theory was proved to be incorrect in the late 1960s, when it was discovered that the sharks were able to jump along the rapids of the San Juan River almost like the salmon.

The freshwater shark, also known as the Caribbean bull shark, has a high tolerance of fresh water, which enabled it to adapt to the water of the San Juan River, allowing it to travel up the river and reach Lake Nicaragua. Over time the shark totally adapted to the freshwater, and it was even able to reproduce in it. The sharks were aggressive and local fishermen were generally afraid of them. During the Somoza dynasty a shark-fin processing plant operated on the shores of the river, through which they caught and killed thousands of sharks each year. The shark population thus declined, and nowadays only a few of them remain.

Ecological Threats

Despite the lake’s large ecosystem, Lake Nicaragua faces problems of contaminations which could become much worse if they are not tended to. The situation was publicly acknowledged by numerous institutions, organizations and citizens as well, but as of today there are no national plans for action. Some of the principal threats are toxic waste from opencast mining, aerial fertilizing, and fumigating mining, which causes loss of aquatic and riparian habitats, and thus the disappearance of a number of fish species, birds and mammals.

But the three main and most serious ecological threats are the discharge of wastewater, agricultural industry and introduction of new fish into the lake. Wastewater generally comes from the large urban zones such as Granada, Rivas and Juigalpa, which all lead their sewage from their residential and industrial areas right into Lake Nicaragua. One study suggested that 32 tons of raw sewage enter the lake each day. A 1981 environmental assessment study conducted by the Nicaraguan Institute of Natural Resources and the Environment concluded that half of the sampled water sources were seriously polluted by sewage. The Pennwalt Chemical Corporation proved to be the worst polluter.

The agricultural industries in the coastal areas also represent a serious problem. The fertile soil next to the lake is an excellent place for cattle farming and different plantations. The Chontales, Boaco and Rivas areas are the principal places where the farming is inconsiderate towards the lake’s situation. The nearby agricultural haciendas also gravely affect the lake’s state.

The introduction of new fish inside floating cages was met with strong disapprovals from ecologists and the local community. The problem is that the huge quantity of Tilapia fish generates large waste quantities which need to be absorbed by the lake itself.

The country’s worst drought in 32 years, which occurred in the month of August 2014 is also taking its toll on the lake’s ecosystem. The local government actually recommended locals to grow iguanas instead of chickens to decrease water consumption. There are plans for constructing a canal through the lake which could lead to saltwater and other contamination during the canal’s construction and operation.

Currently the implementations of strict measures would be necessary by the national authorities, to stop the pollution and rescue Lake Nicaragua and its surrounding ecosystem.


The area is known for piratical invasions which occurred up until the constructions of fortifications on the San Juan River in the 17th century. After the Spanish rule ended in 1820 discussions were on about the construction of a canal in the country, from the Atlantic to the Pacific. The route up the San Juan River, across the lake would be completed by the channel dug through the Rivas Isthmus.

After the discovery of gold in California in 1848 by Cornelius Vanderbilt, the New York millionaire constructed the Vanderbilt Road. Through this road gold prospectors from New York were transported up the river and over the lake, completing the final stage to the Pacific by stagecoach, so they could take a ship up to San Francisco. This arrangement recovered interest for a potential trans-Nicaragua canal. But after the Panama Canal was completed in 1914, this interest faded away.

To crush the competition of the Panama Canal, the United States secured all rights to a canal on the Nicaraguan route in the Bryan-Chamono Treaty of 1916, which was rescinded both by the US and Nicaragua in 1970. The idea of another canal in the country still resurfaced occasionally.

In 2014 the Government of Nicaragua actually offered a 50-year concession to the Hong Kong Nicaragua Canal Development Investment Company to build a canal over the country starting December 2014. The project met with heavy protests, which have led to doubts about the project ever happening.

Tourism and Recreation

Besides the numerous activities one can do and enjoy on the many islands of the lake, there are also other activities one can pursue in the area. One of the best views of the region is offered by the Mombacho volcano, where tourists can enjoy a fairly easy hike up to the mouth of the volcano. The area is also a great place for wildlife watching, since you can encounter monkeys, snakes, deer, reptiles, birds and insects during your hike. The volcano is home to several endemic species, including the Mombacho salamander. There’s a tourist center along the marked road, and you can even hire a professional guide to lead your way.

You can also go on diverse boat excursions on the San Juan River. The nearby Indio-Maiz Biological Reserve, with its plentiful rainforest and wildlife, is home to many exciting endangered species which can be spotted, such as the howlers, white-faced monkeys, spider monkeys, jaguars, giant anteaters, crocodiles, toucans, scarlet macaws and rare and beautiful orchids. The best way to explore the islands is through arranged boat excursions.

Lake Nicaragua Map