Nicaragua (officially the Republic of Nicaragua Spanish: República de Nicaragua [reˈpuβlika ðe nikaˈɾaɣwa] ^ⓘ) is a country in Central America, bordering both the Caribbean Sea and the North Pacific Ocean, between Costa Rica and Honduras. Nicaragua is the largest country in Central America in square kilometers.

Nicaragua covers a total area of 130,370 square kilometers (119,990 square kilometers of which is land area) and contains a variety of climates and terrains. The country's physical geography divides it into three major zones: the Pacific lowlands, the wetter, cooler central highlands, and the Caribbean lowlands.

The natural regions of Nicaragua are the Pacific lowlands, central highlands, and Caribbean lowlands.

The Pacific lowlands extend about 75 kilometers inland from the Pacific coast. Most of the area is flat, except for a line of young volcanoes, many of which are still active, running between the Golfo de Fonseca and Lago de Nicaragua. These peaks lie just west of a large crustal fracture or structural rift that forms a long, narrow depression passing southeast across the isthmus from the Golfo de Fonseca to the Río San Juan.

The rift is occupied in part by the largest freshwater lakes in Central America: Lago de Managua (56 kilometers long and 24 kilometers wide) and Lago de Nicaragua (about 160 kilometers long and 75 kilometers wide). These two lakes are joined by the Río Tipitapa, which flows south into Lago de Nicaragua. Lago de Nicaragua in turn drains into the Río San Juan (the boundary between Nicaragua and Costa Rica), which flows through the southern part of the rift lowlands to the Caribbean Sea.

The valley of the Río San Juan forms a natural passageway close to sea level across the Nicaraguan isthmus from the Caribbean Sea to Lago de Nicaragua and the rift. From the southwest edge of Lago de Nicaragua, it is only nineteen kilometers to the Pacific Ocean. This route was considered as a possible alternative to the Panama Canal at various times in the past.

Surrounding the lakes and extending northwest of them along the rift valley to the Golfo de Fonseca are fertile lowland plains highly enriched with volcanic ash from nearby volcanoes. These lowlands are densely populated and well cultivated. The natural vegetation of the Pacific lowlands is dry forest, but much of it has been converted to agriculture or pasture. More directly west of the lake region is a narrow line of ash-covered hills and volcanoes that separate the lakes from the Pacific Ocean. This line is highest in the central portion near the cities of León and Managua.

Because Western Nicaragua is located where two major tectonic plates collide, it is subject to earthquakes and volcanic eruptions. Although periodic volcanic eruptions have caused agricultural damage from fumes and ash, earthquakes have been by far more destructive to life and property. Hundreds of shocks occur each year, some of which cause severe damage. The capital city of Managua was virtually destroyed in 1931 and again in 1972.