Yosemite National Park use by action of the U.S. federal government, and set a precedent for the 1872 creation of Yellowstone as the first national park. Yosemite Valley and the Mariposa Grove were ceded to California as a state park, and a board of commissioners was proclaimed two years later. Galen Clark was appointed by the commission as the Grant's first guardian, but neither Clark nor the commissioners had the authority to evict homesteaders (which included Hutchings). The issue was not settled until 1872 when the homesteader land holdings were invalidated by the U.S. Supreme Court. Clark and the reigning commissioners were ousted
Yosemite National Park alpine glaciers, bucking established scientists such as Josiah Whitney, who regarded Muir as an amateur. Muir wrote scientific papers on the area's biology. Landscape architect Frederick Law Olmsted emphasized the importance of conservation of Yosemite Valley. Overgrazing of meadows (especially by sheep), logging of giant sequoia, and other damage caused Muir to become an advocate for further protection. Muir convinced prominent guests of the importance of putting the area under federal protection; one such guest was Robert Underwood Johnson, editor of "Century Magazine". Muir and Johnson lobbied Congress for the Act that created Yosemite National Park on October 1, 1890.