The site was originally inhabited by the
Gabrieleno people, and was known as Clara's Basin. Around 1880, William K. Henninger settled in a small basin above Altadena. Henninger was born in Virginia and had been a gold prospector. The area was originally purchased by Mr. Peter Stiel through the
Homestead Act. Stiel's friend Henninger had been squatting on the area since 1884. Henninger was given the title captain by the other miners he worked with as a sign of respect. Henninger married an Indigenous California woman known as Teresa. Their firstborn, a son named Natividad, was baptized at the
San Gabriel Mission in December 1858. They had three daughters: Louisa, Susana, and Jesefa. William K. Henninger built a house and a
cistern for water storage. He planted fruit, vegetables, and nut trees and harvested hay. The produce he carried into town, a mile and a half down the steep trail that ended in
Eaton Canyon. In 1892, Henninger was visited by T. P. Lukens and R. J. Busch, who started the very first experimental reforestation in California at Henninger Flats. Upon his death in March 1894, the property was willed to his daughters. The property was auctioned in 1895 to Harry C. and Harriet M. Allen of nearby
Pasadena. In October 1895, the Allens sold the property for $5,000 to four men who then sold the property to the Mt. Wilson Toll Road Company for $76,600 as part of the
Mount Wilson Toll Road. In 1903, under the direction of Lukens, a
nursery was established at Henninger Flats. During the years that followed the road was widened to accommodate the passage of equipment up to the
observatory at
Mt. Wilson. By 1917 the road was widened to the present width of twelve feet. Since 1928, the flats have been used as a high elevation forest nursery by the
Los Angeles County Fire Department. ==Hiking==