Sierra Leone, officially the Republic of Sierra Leone, informally Salone, is a country on the southwest coast of West Africa. It is bordered by Liberia to the southeast and Guinea to the northeast. Sierra Leone has a tropical climate with a diverse environment ranging from savanna to rainforests, a total area of 71,740 km2 and a population of 7,092,113 as of the 2015 census. The capital and largest city is Freetown.