Cattlemen came to the park in the later half of the 19th century to graze their cattle and tap springs to water them. Miners searched the landscape for valuable ores, while homesteaders arrived in the 1900s to claim a piece of land for their own. Vestiges of each of these arrivals are noted in the park's 501 known archaeological sites, its 88 historic structures, and within the more than 123,000 items in the park's museum collections.
A key individual in the drive to see the desert landscape preserved as part of the National Park System was Minerva Hamilton Hoyt, who grew up in Mississippi during the Civil War Reconstruction Era but moved to Southern California after marrying and fell in love with the desert. It was during trips into the desert to collect plants for her gardens that she not only came to appreciate the desert vegetation, but saw the careless destruction of the land by those who viewed the Joshua trees and other cacti as worthless.
Not only did Mrs. Hoyt stage exhibitions of desert vegetation in places such as Boston, New York, and London in the late 1920s, but she founded the International Deserts Conservtaion League with the intention of preserving desertscapes. The attention she garnered through these efforts led Frederick Law Olmstead Jr., the noted landscape architect, to appoint her to a commission to recommend new state parks for California.
It was Mrs. Hoyt's belief that the National Park Service was best suited to preserve large swaths of desert that spurred her campaign to have the Joshua Tree area set aside as part of the National Park System. Her work led to her introduction to President Franklin Roosevelt and a friendship with his secretary of the Interior, Harold Ickes.
When the Park Service proposed to recommend a 138,000-acre park, Mrs. Hoyt, who wanted one in the range of 1 million acres, complained to Secretary Ickes and succeeded in having Interior officials propose a larger area for protection.
In 1936 President Franklin D. Roosevelt set aside 825,340 acres of the landscape as a national monument, but 14 years later Congress transferred 289,500 acres out of the monument and back into the public domain for mining and grazing. In 1994, however, the California Desert Protection Act returned that land back to the monument and redesignated Joshua Tree as a national park. Then, between 1999 and 2000, another 25,000 acres of land within the park's boundaries that had been privately owned were added to the park as part of the purchase by the federal government and the Wildland Conservancy of more than 600,000 acres from the Catellus Corporation.