United States is 8.9 times larger than Mauritania.
Area: 1,030,700 km2 World Factbook
Population: 3,516,806 (July 2014) World Factbook
Mauritania, officially the Islamic Republic of Mauritania, is a country in the Maghreb region of western North Africa. 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