Yosemite Valley a National Historic District and as a California Historical Landmark. After the creation of the Park Service, many separate hotel owners held separate concession contracts. The Yosemite Park Company had built the Yosemite Lodge and Yosemite Village had its own group of merchants. Fire had destroyed a number of the original valley hotels and concession owners came and went until Park Service forced the two largest companies to merge in order that one single concession contract could be given. In 1925 the two family-run companies became the Yosemite Park and Curry Company and went on to build and run the
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.