The Caribbean coast, known as the Mosquito (or Miskito) Coast or Mosquitia, consists of low, flat, wet, tropical forest, extending into pine savannas 80–160 km (50–100 mi) inland. The coastal lowland rises to a plateau covering about one-third of the total area. This plateau is broken by mountain ranges extending eastward from the main cordillera to within 64–80 km (40–50 mi) of the Caribbean coast. The mountainous central area forms a triangular wedge pointed southeast, rising at its highest to some 2,000 m (6,600 ft). The plains and lake region, in a long, narrow structural depression running northwest to southeast along the isthmus, contains a belt of volcanoes rising to 1,500 m (5,000 ft) and extending from the Gulf of Fonseca to Lake Nicaragua. In this region is located Lake Managua, at 41 m (136 ft) above sea level, which drains through the Tipitapa Channel into Lake Nicaragua, at 32 m (106 ft) above sea level, which, in turn, drains through the San Juan River eastward into the Caribbean. Lake Nicaragua is about 160 km (100 mi) long and 65 km (40 mi) wide at the widest point, while Lake Managua is 52 km (33 mi) long by 25 km (16 mi) wide.

The principal waterways are the Coco (or Segovia) River, navigable up to 240 km (150 mi) inland from the eastern Mosquito Coast, and the San Juan, navigable to within a few miles of the Caribbean, where a series of rapids halts transportation.

When we speak about the relief of a country we are referring not only to the mountains and hills, but also to valleys and depressions. In short, relief has to do with the changes in altitude that the different geographic accidents exhibit. In Nicaragua, as was mentioned earlier, we can observe three macro regions by virtue of their general topographic characteristics: Pacific, Central, and Caribbean. These, in turn, can be further subdivided into the actual systems responsible for the formations within. To make sure that things do not get confused, a geographic accident is any variation in the terrain of a given area (thus, it would include mountains, depressions, rivers, lakes, and so on); a range is a group of mountains that lie together; whereas a system can be a group of ranges that share the same origin. Systems, then, are responsible for the existence of ranges.

Some 60 million years ago, North and South America were two separate continents drifting towards each other. North America ended in a pointy peninsula on what is now Nicaragua’s Central Region, more specifically, Nicaragua’s Central Shield. The Caribbean Region is a product, for the most part, of the sediments brought down from these mountains by the rivers that flowed eastward towards the then Atlantic Ocean (today, the Caribbean Sea). The Pacific Region is much newer than the other two, barely a million years old, and was formed by the emergence of the volcanic chains that today constitute the Coastal Highlands. The volcanic activity activated the fault lines that formed the Great Rift and created the depressions that eventually became Lakes Managua and Nicaragua. The two continents finally fused together pretty much at the same time as the Pacific Region emerged, as Costa Rica and Panama surfaced from the ocean.

Description of the Relief of the country

While the three macro regions in Nicaragua exhibit rock formations that belong to the three general classifications (i.e. igneous, sedimentary, and metamorphic), the Pacific Region tends to have more igneous and sedimentary rocks; the Central Region, more metamorphic rocks; while the Caribbean Region tends to have more sedimentary rocks. It is important to clarify that the type of rocks found in a given area is not a determinant of the potential fertility of the area. The chemical composition of the soil itself will determine the fertility and productive capacity of the land (along with the existence of water sources and such).

Pacific Region

The Pacific Region holds the vast majority of the country?s population. In all, population density in this region reaches 134 people per square kilometre, against 36 for the national average. The reasons behind such high population density in relation to other areas has to do with the physical make up of the Pacific Region. The existence of a large volcanic chain and other volcanic formations, plus the ready access to water sources, has been historically a magnet for human settlements. Geologically, it can be sub classified into two main sub regions: the Sedimentary Coastal Area, and the Quaternary Volcanic region.