Hendy Woods State Park, State park in Mendocino County, United States.

Hendy Woods State Park covers 816 acres in the Anderson Valley, about 20 miles from the coast, and holds two old-growth coast redwood groves: Big Hendy (80 acres) and Little Hendy (20 acres). Some trees exceed 300 feet and may be nearly 1,000 years old. Madrone, Douglas fir and California laurel grow among them, and 3.3 miles of the park border the Navarro River.

Joshua Hendy, an English-born blacksmith who came to California during the Gold Rush, built a large sawmill on the Navarro River and on his death in 1891 willed the land to his nephews on condition the redwood groves be protected. His nephew Samuel sold it, and it passed through the Pacific Coast Lumber, Albion Lumber, Southern Pacific Land and Masonite companies without being logged. In 1958 the state bought about 600 acres from Masonite for US$350,000, and the park was dedicated on July 7, 1963.

The park's name honours Joshua Hendy, the English-born blacksmith who willed the redwood groves to be protected. The Anderson Valley Unity Club, a local women's service group, campaigned to save the groves after Al Strowbridge spoke to them in 1938, and it built the accessible trail through the redwoods in 1980–1981.

Two campgrounds sit between the Big Hendy and Little Hendy groves, holding 92 campsites in all, plus four cabins and 25 picnic sites along the Navarro River. A wheelchair-accessible trail runs through the redwoods, and the park is one of only two in Mendocino County fully compliant with the Americans with Disabilities Act. Reach the entrance via Philo–Greenwood Road, just off State Route 128.

During the 1960s and 1970s, a man named Petrov Zailenko, known as the Hendy Hermit, lived alone within the park for over ten years. His solitary life in the forest remains a curious part of the park's story that few visitors know about.