William Andrews Clark, Sr. (January 8, 1839 – March 2, 1925) was an American politician and entrepreneur, involved with mining, banking, and railroads.
Clark was born in Connellsville, Pennsylvania. He moved with his family to Iowa in 1856 where he taught school and studied law at Iowa Wesleyan College. After working in quartz mines in Colorado, in 1863, Clark made his way to Montana to find his fortune in the gold rush.
He settled in the capital of Montana Territory, Bannack, Montana, and began placer mining. Though his claim paid only moderately, Clark invested his earnings in becoming a trader, driving mules back and forth between Salt Lake City and the boomtowns of Montana to transport eggs and other basic supplies.
He soon changed careers again and became a banker in Deer Lodge, Montana. He repossessed mining properties when owners defaulted on their loans, placing him in the mining industry. He made a fortune with small smelters, electric power companies, newspapers, railroads and other businesses, becoming known as one of three "Copper Kings" of Butte, Montana, along with Marcus Daly and F. Augustus Heinze.
Between 1884 and 1888, Clark constructed a 34-room,