km²
Square Kilometer
A square kilometer is a unit of area equal to 1,000,000 square meters or 100 hectares. It is used for measuring the area of cities, countries, lakes, and other large geographic regions. One square kilometer equals approximately 0.386 square miles.
History
The square kilometer is derived from the kilometer. It is the standard unit for expressing the area of countries and large geographic features. For example, France covers approximately 640,679 km² and the United States covers approximately 9,833,520 km².