Walter Cooper, son of Andrew H. and Sarah E. (McGillvra) Cooper, of Sterling, Cayuga County, New York, was born on July 4, 1843. Six years later the Cooper family moved to Shiawassee County, Michigan. On the death of Andrew Cooper in 1851, Walter was sent to live with a relative in Lansing, Michigan, while the remainder of his family--his mother and five brothers--returned to New York. At the age of fifteen, Cooper began his journey west. He arrived in Leavenworth, Kansas, in 1858, where he worked at odd jobs until heading for Colorado Territory. In 1860 Cooper accompanied prospectors to the San Juan Mountains, returning to Colorado the following year. While in Colorado, he periodically worked as a scout for the First Colorado Regiment. In February of 1864, Cooper arrived in Alder Gulch, Montana Territory. After brief stints as a miner, a freighter, and a hunter, he returned to mining and continued in that profession from 1865 to 1869. In 1870 Cooper moved to Bozeman, where he opened a business handling and manufacturing guns, ammunition and fishing tackle. Also in 1870, on April 19, he married Mariam D. Skeels, daughter of Nelson Skeels of Boulder Valley, Montana Territory. Cooper was involved in many different business interests in Bozeman. In addition to operating a firearms and sporting goods business, he dealt in the fur trade and in general merchandise. He also organized and was active in several additional business ventures. In 1884 he was instrumental in organizing the Rocky Fork and Cooke City Railway and, consequently, in developing the coal fields at Rocky Fork. Later, in 1889, he organized the Bozeman Waterworks Company, which built a water system for the city of Bozeman. Then in 1902 he founded the Walter Cooper Company, a lumbering operation that furnished railroad ties to several large railroad companies. Additionally, Cooper was involved in the Eastern Montana Mining and Smelting Company and the Bozeman Gold and Silver Mining Company. Walter Cooper was also active in local and state politics in the Democratic party. On the state level, he was elected in both 1884 and 1889 as a delegate to the Constitutional Convention and served as a committee chairman at both sessions. He was also elected, in 1895, to the State Legislature. Locally, Cooper served as an alderman, was an incorporator of the city of Bozeman in 1883, served as a member of the first City Council, was the first president of the Bozeman Board of Trade, and, in 1910, was elected to the Bozeman Chamber of Commerce. In addition, he served as a member of the Executive Board of Montana State College from 1892 to 1898. Socially, Cooper was an active member of several historical and fraternal organizations. He served as president of the Society of Montana Pioneers in 1892, as president of the Gallatin County Pioneer Society, and as vice president of the Gallatin Valley Club. He was also a member of the Montana Commercial Club, the Bozeman Commercial Club, and the Gallatin Lodge of the Free and Accepted Masons. On May 23, 1924, Walter Cooper died in Bozeman, Montana. He and his wife had three children, two of whom died in infancy. His surviving daughter, Mariam, married Eugene F. Bunker of Bozeman.