In the United States, national forest is a classification of protected and managed federal lands that are largely forest and woodland areas. They are owned collectively by the American people through the federal government and managed by the United States Forest Service, a division of the United States Department of Agriculture. The U.S. Forest Service is also a forestry research organization which provides financial assistance to state and local forestry industry. There are 154 national forests in the United States.

The United States Forest Service (USFS) is an agency within the U.S. Department of Agriculture that administers the nation's 154 national forests and 20 national grasslands covering 193 million acres (780,000 km2) of land. The major divisions of the agency are the Chief's Office, National Forest System, State and Private Forestry, Business Operations, as well as Research and Development. The agency manages about 25% of federal lands and is the sole major national land management agency not part of the U.S. Department of the Interior.