Bonanza was founded after prospectors struck pay dirt in the Bonanza Mine. By the mid-1880s the town had more than 150 buildings and an estimated 1,000 people. By 1890 the gold boom was over. Raw pine boards turned gray, and weeds climbed the rusting mine machinery. The population in 1890 was 118 and a century later is only 16. Mining town life here was well described by resident Anne Ellis in her book, The Life of an Ordinary Woman (1929). Frame buildings and ruins line the main street, and traces of mines, mills, and smelters survive in town and in the surrounding foothills of the San Juan Mountains. The two-story, chinked log Kempner House (1880s), Saguache County LL 56, 10.8 miles northwest of U.S. 285, a T-shaped, cross-gabled house, provides local historian Helen Kempner with a fine view down the Kerber Creek Valley.