United States is 4.2 times larger than Greenland.
Area: 2,166,086 km2 World Factbook
Population: 57,728 (July 2014) World Factbook
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. 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