Nicaragua occupies a landmass of 129,494 km², comparable to that of Greece or New York State. Nearly one fifth of the territory is designated as protected areas like national parks, nature reserves, and biological reserves. The country is bordered by Honduras to the north, the Caribbean Sea to the east, Costa Rica to the south, and the Pacific Ocean to the west.
Nicaragua has three distinct geographical regions: the Pacific Lowlands, the Amerrique Mountains (North-Central Highlands), and the Mosquito Coast (Atlantic Lowlands).
Located in the west of the country, these lowlands consist of a broad, hot, fertile plain. Punctuating this plain are several large volcanoes of the Cordillera Los Maribios mountain range, including Mombacho just outside Granada, and Momotombo near León. The lowland area runs from the Gulf of Fonseca to Nicaragua's Pacific border with Costa Rica south of Lake Nicaragua. Lake Nicaragua is the largest freshwater lake in Central America (20th largest in the world), and is home to the world's only freshwater sharks (Nicaraguan shark). The Pacific lowlands region is the most populous, with over half of the nation's population. The capital city of Managua is the most populous and it is the only city with over 1.5 million inhabitants.
Most of the Pacific zone is tierra caliente, the "hot land" of tropical Spanish America at elevations under 2,000 feet (600 meters). Temperatures remain virtually constant throughout the year, with highs ranging between 85° and 90°F (29°–32°C). After a dry season lasting from November to April, rains begin in May and continue to October, giving the Pacific Lowlands 40 to 60 inches (1,000–1,500 mm) of precipitation. Good soils and a favorable climate combine to make western Nicaragua the country's economic and demographic center. The southwestern shore of Lake Nicaragua lies within 15 miles (25 km) of the Pacific Ocean. Thus the lake and the San Juan River were often proposed in the 19th century as the longest part of a canal route across the Central American isthmus.
In addition to its beach and resort communities, the Pacific Lowlands is also the repository for much of Nicaragua's Spanish colonial heritage. Cities such as León and Granada abound in colonial architecture and artifacts; Granada, founded in 1524, is the oldest colonial city in the Americas.
The Central Highlands are a significantly less populated and economically developed area located in the north but narrow southeastward between Lake Nicaragua and the Caribbean. Forming the country's tierra templada, or "temperate land," at elevations between 2,000 and 5,000 feet (600–1,500 meters), the highlands enjoy mild temperatures with daily highs of 75° to 80°F (24°–27°C). This region has a longer, wetter rainy season than the Pacific Lowlands, making erosion a problem on its steep slopes. Rugged terrain, poor soils, and low population density characterize the area as a whole, but the northwestern valleys are fertile and well settled.
The area, however, has a cooler climate than the Pacific Lowlands. About a quarter of the country's agriculture takes place in this region, with coffee grown on the higher slopes. Oaks, pines, moss, ferns and orchids are abundant in the cloud forests of the region.
Bird life in the forests of the central region includes resplendent Quetzal, goldfinches, hummingbirds, jays and toucanets.
This large rainforest region is irrigated by several large rivers and very sparsely populated. The Rio Coco is the largest river in Central America, it forms the border with Honduras. The Caribbean coastline is much more sinuous than its generally straight Pacific counterpart; lagoons and deltas make it very irregular.
Nicaragua's Bosawás Biosphere Reserve is located in the Atlantic lowlands, it protects 1.8 million acres (7,300 km²) of La Mosquitia forest - almost seven percent of the country's area - making it the largest rainforest north of the Amazon in Brazil.
Nicaragua's tropical east coast is very different from the rest of the country. The climate is predominantly tropical, with high temperature and high humidity. Around the area's principal city of Bluefields, English is widely spoken along with the official Spanish. The population more closely resembles that found in many typical Caribbean ports than the rest of Nicaragua.
A great variety of birds can be observed including eagles, turkeys, toucans, parakeets and macaws. Animal life in the area includes different species of monkeys, anteaters, white-tailed deer and tapirs.