Opened in July 1928 after being donated to Yuba County, Hammon Grove was a tiny remnant of the more than 10,000 acres controlled by Wendell P. Hammon’s dredging companies. Hammon arrived in California in 1875 and by 1902 had developed the machinery needed to dredge gold from more than one billion cubic yards of tailings, averaging 22 feet deep, left by upstream hydraulic mining. His Yuba Dredge No. 20 was the world’s largest. All dredging in the Yuba River Basin had ceased by 1968, but the resulting rock piles will remain for many generations to come.