Muir, John (1838–1914), a United States naturalist and conservationist. He discovered and explored the glacier in Alaska now known as Muir Glacier, and was an early authority on glacial geology. He led campaigns to create Yosemite National Park, to establish national forest reserves, and to enact conservation laws. Muir Woods National Monument, a redwood grove near San Francisco, is named for him.

Muir wrote many articles and books about the mountains and a life close to nature. In plain, vigorous prose he sought and eventually won public support for enlargement of the national forest and parks systems. He declared:

The forests of America, however slighted by man, must have been a great delight to God; for they were the best He ever planted.

Muir was born in Scotland. He emigrated with his family to a farm near Portage, Wisconsin, in 1849. From boyhood he demonstrated a remarkable aptitude for mechanical invention. As a student at the University of Wisconsin (1859–63), Muir chose courses, mainly in chemistry and geology, that interested him rather than working for a degree. He became an ardent botanist and made several collecting trips on foot through the upper Midwest. During 1867–68 he walked from Indiana to the Gulf of Mexico and on to California, making notes and sketches of rock formations, trees, flowers—all the things he called “the inventions of God.”

From 1868 to 1874 Muir lived alone in Yosemite, then he roamed Nevada and Utah. He explored Alaska in 1879, 1880, and 1890, and subsequently traveled throughout the world to visit forests. Muir owned a fruit farm at Martinez, California, but spent much of his time, until his death, in the high Sierras. “Going to the mountains is like going home,” he said.

His books include: The Mountains of California (1894); Stickeen (1909), about his Alaska adventures: The Yosemite (1912); The Story of My Boyhood and Youth (1913).