Ansel F. Hall (1894-1962) was an American naturalist. He was the first Chief Naturalist and first Chief Forester of the United States National Park Service. Hall graduated in 1917 from the University of California with a degree in forestry. He joined the then-infant National Park Service as a ranger in Sequoia National Park. His Park Service career was then interrupted by military service in France during World War I. From 1920 to 1923, he served as the first Park Naturalist of Yosemite National Park, where he established innovative interpretative programs, founded the Yosemite Museum Association, made geological models and native crafts, mounted natural history specimens, and edited the seminal Handbook of Yosemite National Park, published in 1921. Hall left the Park Service in 1938 to operate concessions in Mesa Verde National Park. Later he worked as a consultant in park design and interpretation and wrote books on the topic.