The Stock-Raising Homestead Act of 1916 provided settlers 640 acres (260 ha) of public land—a full section or its equivalent—for ranching purposes. Unlike the Homestead Act of 1862 or the Enlarged Homestead Act of 1909, land homesteaded under the 1916 act separated surface rights from subsurface rights, resulting in what later became known as split estates. The subsurface rights, also known as mineral rights, are the foundation of recent oil and gas law in the United States. Under the act no cultivation of lands was required, but some range improvements were mandated as necessary.