Gabon has a population that is estimated at 1,545,255. Historical and environmental factors caused Gabon's population to decline between 1900 and 1940.Gabon has one of the lowest population densities of any country in Africa, and the fourth highest Human Development Index in Sub-Saharan Africa.
Libreville, the capital of Gabon, is one of the most expensive cities on the African continent with up market bars, elegant French restaurants and pricey boutiques though it is almost impossible to buy very much because of the prohibitive costs.
The main river in Gabon, Ogooue River, arcs across the entire country, with major tributaries including Ivindo and Mpassa. Its mouth is at Port Gentil, on the Atlantic Coast, and it originates in the Republic of the Congo.