James Gaius Watt was an American lawyer, lobbyist, and civil servant who served as U.S. Secretary of the Interior in the Ronald Reagan administration from 1981 to 1983. He was described as "anti-environmentalist" and was one of Ronald Reagan's most controversial cabinet appointments.

The United States secretary of the interior is the head of the United States Department of the Interior. The secretary and the Department of the Interior are responsible for the management and conservation of most federal land along with natural resources, leading such agencies as the Bureau of Land Management, the United States Geological Survey, Bureau of Indian Affairs and the National Park Service. The secretary also serves on and appoints the private citizens on the National Park Foundation Board. The secretary is a member of the United States Cabinet and reports to the president of the United States. The function of the U.S. Department of the Interior is different from that of the interior minister designated in many other countries.