• Military Menu                       

• Introduction
• Systems
• Facilities
• Agencies
• Industry
• Operations
• Countries
• Hot Documents
• News
• Reports
• Policy
• Budget
• Congress
• Links

• WMD
• Intelligence
• Homeland Security
• Space

Sierra Leone - Geography

The Republic of Sierra Leone is located on the West Coast of Africa, between latitudes 7 and 10 north and longitudes 10.5 and 13 west. The Republic of Guinea is to the north and northeast; Liberia is to the east and southeast, and the Atlantic Ocean on the west and south. It has 300 miles of coastline.

The Republic of Sierra Leone, roughly circular in shape — its north-south axis is about 215-miles long and the east-west one about 190 miles — is a compact country of 27,925 square miles located in the southwestern part of the great bulge of West Africa. Lying between the seventh and tenth parallels north of the equator, it is bounded on the west by the Atlantic Ocean and inland by Guinea and Liberia. Its varied terrain includes the striking, mountainous Sierra Leone Peninsula; a zone of low-lying coastal marshland along the Atlantic Ocean; and a wide plains area extending inland to about the middle of the country. East of the plains the land rises to a broad, moderately ele- vated plateau from which emerge occasional hill masses and moun- tains that include West Africa’s highest point.

Generally fertile soils occur along the coast, but soils of the inland area have deteriorated over large areas as the result of excessive use by man and his destruction of the natural vegetation cover. Mineral deposits of economic significance exist, including iron ore, bauxite, titanium ores, and the more glamorous diamond.

From an approximate 70-mile coastal belt of low-lying land, the country rises to a mountain plateau near the eastern frontier rising 4000 to 6000 feet with a rich timber forest region. The Western Area encompasses the Sierra Leone Peninsula, on which the capital and main commercial centre of Freetown stands; is 24 miles long and 10 miles wide.

A mountainous promontory, it rises in places to 300 feet above sea level - one of the few parts of the West African Coast where there is high land so near the sea. Where the lush green forest spills down hillsides to meet the most beautiful white sandy beaches along the Atlantic Ocean.

This 27,925 square mile (73,326 sq km) country has a population of approximately 4.5 million people. Sierra Leone is divided into four main Provinces, West, North, East and South. There are twelve Districts in the entire country.

Most of the country is underlain by rocks of Precambrian age (Archaean and Proterozoic) with a coastal strip about 50 km in width comprising marine and estuarine sediments of Tertiary and Quaternary to recent age. The Precambrian (mainly Archaean) outcrops over about 75% of the country and typically comprises granite-greenstone terrain. It represents parts of ancient continental nuclei located on the edge of the West African Craton. Regional reconnaissance mapping indicates that the Archaean basement can be subdivided into infracrustal rocks (gneisses and granitoids); supracrustal rocks (containing greenstone belts); and basic and ultrabasic igneous intrusions. The infracrustal gneisses and granitoids were formed and reworked during two major orogenic cycles, an older Leonean episode (~2,950-3,200 Ma) and a younger Liberian episode (~2700 Ma).

The Leonean orogenic episode commenced with the intrusion of a basic igneous suite (the Pre-Leonean amphibolites) and by the formation of a greenstone belt represented by the Loko Group which is now deeply eroded. The Loko Group comprises amphibolites, silimanite quartzites and ironstones. It appears to have formed on a gneiss/granitoid basement in which several granitoid bodies related to an earlier plutonicorogenic episode have been distinguished mainly in the northern part of the country. Only the main deformational phase of the Leonean orogenic episode which resulted in folds and fabrics trending.

Natural physical features divide the country into four main geographic regions. In the east a broad area of low plateaus surmounted in places by mountain and hill masses — together with a zone of erod- ed foothills on the area’s western edge — constitutes the Interior Pla- teaus and Mountains Region. (This region constitutes in fact a western extension of the Guinea Highlands from neighboring Guinea.) To the west of this region lies the almost equally large Interior Low Plains Region, which in turn merges into the narrow Coastal Swampland Region paralleling the Atlantic Ocean. The fourth region, comparatively minute in area but physiographically highly distinctive, includes only the Sierra Leone, or Freetown, Peninsula.

Interior Plateaus and Mountains

This region, which encompasses roughly the eastern half of the country, consists chiefly of a large area of plateaus having elevations of above 1,000 feet to about 2,000 feet. Rising above the relatively flat surface are several mountain masses, including the Loma Mountains, in which is located Loma Mansa (Bintimani), at 6,390 feet the highest point in West Africa west of the Cameroon Mountains; the Tingi Mountains (sometimes called Tingi Hills), also rising at one point to over 6,000 feet; and the lower Nimini and Sula mountains and Gola, Gori, and Jojina hills. Isolated hills (inselbergs) are also found at many places throughout the plateaus.

In the region’s southern section erosion has resulted in a large area of rolling terrain, forty or so miles wide at points and having elevations between 500 and 1,000 feet and scattered low hills. This area now forms the upper basin of the Moa River. The western edge of the plateau exhibits different stages of erosion and in places is characterized by steep-sided river valleys and highly dissected hills. Among the latter the most prominent are the Kangari and Kambui hills. The Kambui Hills, formed of extremely ancient (pre-Cambrian) schists, have important deposits of minerals of economic significance. Such schists are found also in the Sula and other mountains and hills in the region, and they too have associated minerals with them.

The southern part of the region has a somewhat longer rainy season than other areas of Sierra Leone. The rain and the soil conditions make it suitable for growing cocoa and coffee. In general the vegetation has been greatly modified by the practice of bush fallow cultivation, but a considerable amount of secondary forest was still found in this section in the early 1970s. In the region’s more northerly part less rainfall is received, and the vegetation is mainly of a derived savanna type. In the mid-1970s subsistence agriculture characterized the var- ious ethnic groups in the northern area, and cattle raising was a principal industry among the seminomadic Fullah.

Interior Low Plains

The interior plains range in width from under thirty miles near the Liberian border to some seventy or eighty miles in their central and northern parts. Stretching eastward from the coastal swamps and the bordering wet grasslands to the foothills of the plateau region, the plains have elevations mostly from about 100 feet to 500 feet (where they meet the foothills). Areas of residual hills rise at places to 1,000 feet and over, however.

Vegetation over most of the region consists of what is known locally as farm bush, secondary forest, and cultivated crops. A large area in the northeastern part of the region, averaging about twenty miles in width and roughly ninety to 100 miles in length, is covered mostly by swampy grassland; this area is known as the bolilands. Small inland valley swamps, used for rice cultivation, also occur at many other places throughout the region.

Coastal Swampland

This region comprises a zone varying from about five to twenty-five miles in width along the coast. The region is characterized by numerous estuaries whose river channels, as in the case of the Sierra Leone River, continue under the sea and across the continental shelf, indicating submergence of the coast in very recent geological times.

Mangrove swamps lined much of the coast, behind which marine and freshwater swamps occupy large areas. North of Freetown, however, the coast extending to the estuary of the Little Searcies River is fronted in places by beach ridges and in one section by the cliffs of a low plateau. Soils in this coastal stretch are relatively good and produce cash crops for the Freetown market. Beach ridges also front a long stretch of the coast in the southernmost part of the region but have generally infertile soils. A notable feature of this southern section is the large area of riverain grassland that lies behind the coast.

Sierra Leone Peninsula

The mountainous Sierra Leone Peninsula, on which Freetown is located, is twenty-five miles long and averages about ten miles in width. It is treated as a separate geographic region because its unusual features bear no direct relationship to those of the adjacent coastal region or for that matter to the other two geographic regions.

The peninsula consists chiefly of igneous rocks that form — with the nearby Banana Islands — the visible part of a much larger igneous mass submerged beneath the sea. It is believed to have been uplifted in relatively recent geological times judging from its present-day relief and height, which exceeds 2,000 feet in several places and reaches a maximum of over 2,900 feet. Most of the peninsula’s hills are includ- ed in a forest reserve established to halt erosion and preserve the watershed as a source of water supply for domestic purposes.

Around the base of the mountains is a strip of land about one mile wide consisting of lateritic hardpan. Variations in earlier sea levels have left a number of raised beaches in this strip, the uppermost about 160 feet above the present-day sea level. Freetown and other settlements are mainly situated on these raised beaches. The present coast consists of sand ridges and some areas of mangrove swamp.

Drainage

The country drains entirely into the Atlantic Ocean through nine roughly parallel, principal river basins that run generally northeast to southwest and some five small basins of river systems confined to the coastal area. Five of the main basins lie completely within the coun- try, including those of the Rokel (or Seli), Gbangbar, Jong, Sewa (the largest basin, encompassing nearly 5,500 square miles), and Waanje rivers. To the north of the Rokel basin lie the basins of the Great Searcies and Little Searcies rivers, both of which rise in the Fouta Djallon highlands of neighboring Guinea (where they are known respectively as the Kolente and Kaba rivers). In the south are the basins of the Moa River system, which extends into southeastern Guinea and Liberia, and of the Mano River, which with its tributaries drains part of northern Liberia.

The heavy wet season rainfall causes a substantial rise in river levels that in places may be fifty or more feet above the dry season low water mark. The main rivers have cut deeply into the interior plains, resulting in stretches of rapids that, with the seasonal variation in water levels, reduce continuous navigability to twenty or thirty some miles of their lower courses; an exception is in the south, where the Kittam and Waanje rivers run for a combined distance of about fifty miles behind and parallel to slightly raised coastal ridges that obstruct the rivers' direct entry to the ocean.

Although considerable areas of inland low-lying swampland are periodically flooded, permanent freshwater lakes are few, and all are comparatively small. Only six lakes have an area of one square mile or more, and the country’s largest. Lake Mape in Pujehun District, is less than eleven square miles.