Harold LeClair Ickes was an American administrator, politician and lawyer. He served as United States Secretary of the Interior for nearly 13 years from 1933 to 1946, the longest tenure of anyone to hold the office, and the second longest-serving Cabinet member in U.S. history after James Wilson. Ickes and Labor Secretary Frances Perkins were the only original members of the Roosevelt cabinet who remained in office for his entire presidency.

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.