4,654 kilometers!
The United States of America is a country in North America with 50 states. The explorer shows the 48 contiguous states, which form a single connected block of land: every state except Alaska and Hawaii. Their farthest-apart points, in Maine and California, are about 4,650 kilometers (2,890 miles) apart.
The U.S. Geological Survey (USGS), a government science agency, worked out the country's extreme distances from its surveys and maps. The two points farthest apart in the 48 states are West Quoddy Head, Maine, and Point Arena, California. The USGS gives the distance between them as 2,892 miles, about 4,650 kilometers.
The width depends on where it is measured. Due west from West Quoddy Head, along the same line of latitude, it is 4,413 kilometers (2,742 miles) to the Pacific Ocean. The shortest coast-to-coast distance, from near Brunswick, Georgia, to near San Diego, California, is 3,362 kilometers (2,089 miles). From north to south, the southern tip of Texas is 2,578 kilometers (1,602 miles) from the 49th parallel, the line 49 degrees north of the equator.
Alaska and Hawaii make the country much wider. The farthest-apart points in all 50 states are Log Point on Elliot Key, Florida, and Kure Island, Hawaii, 9,429 kilometers (5,859 miles) apart. West Quoddy Head, Maine, is 7,775 kilometers (4,831 miles) from Cape Wrangell on Alaska's Attu Island.
The whole country, including the District of Columbia, covers 9,833,517 square kilometers (3,796,742 square miles) of land and water. Alaska alone covers about 18% of that. The Moon's surface has almost four times the area of the whole United States.
The USGS places the geographic center of the 48 states near Lebanon, in Smith County, Kansas. Adding Alaska and Hawaii moves the center of the 50 states to a point west of Castle Rock, in Butte County, South Dakota. The two centers are about 710 kilometers (440 miles) apart.