Kent was also responsible for the establishment of Muir Woods National Monument on 611 acres of land along Redwood Creek that Kent and his wife Elizabeth Tacher Kent had originally purchased in 1905 for $45,000 in an effort to preserve the property's groves of old-growth redwoods. After a local water company began condemnation proceedings in 1907 in an effort to create a reservoir on the site, Kent quickly deeded 295 acres of the property to the U.S. Department of the Interior for the establishment of a national monument under the recently-passed Antiquities Act. Established as a national monument by President Theodore Roosevelt on January 6, 1908, Kent asked the site be named in honor of conservationist John Muir.