Built in 1890 in Butte’s red-light district, the Dumas Brothel grew with the city’s copper boom and became one of its best-known high-class sex houses. Expanded repeatedly as mining wages and customer traffic increased, it developed a distinctive interior, basement cribs, and tunnel connections that helped it continue operating despite reform campaigns and law-enforcement scrutiny. The house outlasted the district’s effective closure by 1917, adapted during World War II by posing as a boardinghouse, and remained active until 1982, when Ruby Garrett’s tax-evasion conviction ended its 92-year run. Preserved afterward, it survives as an unusually intact record of Butte’s vice, labor, and politics.