The United States is the North American country whose capital is Washington, D.C., and whose official currency is the United States dollar.
The country occupies much of the central portion of North America, stretching from the Atlantic Ocean to the Pacific Ocean. It shares land borders with Canada to the north and Mexico to the south, and also includes Alaska and Hawaii. Washington, D.C., located between Maryland and Virginia on the East Coast, has served as the national capital since 1800.
The dollar is issued by the United States Federal Reserve and the U.S. Department of the Treasury. Its international currency code is USD, and the familiar dollar sign is $. The U.S. dollar is also widely used outside the United States and serves as a major reserve and trading currency.
A common confusion is treating Washington, D.C., as a state. It is a federal district, formally named the District of Columbia, and is not part of any U.S. state.