Idaho (USA) is 2.1 times larger than Korea (South).
Area: 99,720 km2 World Factbook
Population: 49,039,986 (July 2014) World Factbook
South Korea, officially the Republic of Korea, is a country in East Asia, constituting the southern part of the Korean Peninsula. The name Korea is derived from Goryeo (also spelt Koryo), a dynasty which ruled in the Middle Ages. Wikipedia
Idaho is a state in the northwestern region of the United States. Idaho is the 14th largest, the 39th most populous, and the 7th least densely populated of the 50 United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Wikipedia