Stephen Tyng Mather (July 4, 1867 – January 22, 1930) was an American industrialist and conservationist who as president and owner of Thorkildsen-Mather Borax Company became a millionaire. With his friend and journalist Robert Sterling Yard, Mather led a publicity campaign to promote the creation of a unified federal agency to oversee National Parks administration, which was established in 1916. In 1917, Mather was appointed as the first director of the National Park Service, the new agency created within the Department of the Interior. He served until 1929, during which time Mather created a professional civil service organization, increased the numbers of parks and national monuments, and established systematic criteria for adding new properties to the federal system.