The greatest distance between two points within the contiguous U.S. is 2,892 miles, stretching from Point Arena, CA to West Quoddy Head, ME.
The United States of America, comprised of fifty states, is the world's third-largest country. It occupies the central part of the North American continent, between Canada and Mexico, and also includes the states of Alaska, at the northwestern edge of the continent, and Hawaii, an island state in the Pacific Ocean.
Here's some fast facts about the United States:
Area: 9,629,091 square kilometers (3,717,813 square miles)
Highest point on mainland: Mount McKinley (6,194 meters/20,322 feet)
Lowest point on land: Death Valley (86 meters/282 feet below sea level)
Hemispheres: Northern and Western
Time zones: Eastern, 7 A.M. = noon GMT; Central, 6 A.M. = noon GMT; Mountain, 5 A.M. = noon GMT; Pacific 4 A.M. = noon GMT; Yukon, 3 A.M. = noon GMT; Alaska and Hawaii, 2 A.M. = noon GMT; western Alaska, 1 A.M. = noon GMT.
Longest distances: 4,662 kilometers (2,897 miles) from east-northeast to west-southwest; 4,583 kilometers (2,848 miles) from south-southeast to north-northwest
Land boundaries: 12,219 kilometers (7,593 miles) total boundary length; Canada 8,893 kilometers (5,526 miles); Mexico 3,326 kilometers (2,067 miles)
Coastline: 19,924 kilometers (12,380 miles)
Territorial sea limits: 22 kilometers (12 nautical miles)
See the following sites to learn more:
Nations Encyclopedia
National Geographic