United States is 128 times larger than Sierra Leone.
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
The United States of America, commonly referred to as the United States, America, and sometimes the States, is a federal republic consisting of 50 states and a federal district. The 48 contiguous states and Washington, D.C., are in central North America between Canada and Mexico. Wikipedia