High Quality Content by WIKIPEDIA articles! Yellowstone National Forest was first established by the General Land Office on March 30, 1891 as the Yellowstone Park Timber Land Reserve of 1,239,040 acres (5,014.2 km2). On May 22, 1902 it became the Yellowstone Forest Reserve with lands of 6,580,920 acres (26,632.0 km2). The reserve was first suggested by General Philip Sheridan in 1882 after a visit to Yellowstone National Park. Sheridan recommended that the park be expanded 40 miles (64 km) to the east and 10 miles (16 km) to the south. Legislation was introduced by Senator George Graham Vest to accomplish this, but it was stalled by local opposition. The American Forestry Association took up the cause, preparing legislation that would allow the United States president to set aside lands as "forest reservations" through an executive order. President Benjamin Harrison then proclaimed the reserve, largely following Sheridan's recommendation, on March 30, 1891. Some areas on the northeast portion of the proposed reservation were excluded to allow mining in the headwaters of the Clark Fork River.