Nigeria is 13 times larger than Sierra Leone.
Area: 923,768 km2 World Factbook
Population: 177,155,754 (July 2014) World Factbook
Nigeria, officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. Wikipedia
Area: 71,740 km2 World Factbook
Population: 5,743,725 (July 2014) World Factbook
Sierra Leone, officially the Republic of Sierra Leone, is a country in West Africa that is bordered by Guinea to the northeast, Liberia to the southeast, and the Atlantic Ocean to the southwest. Sierra Leone is a constitutional republic with a directly elected president and a unicameral legislature. Wikipedia