Ellis Alfred Swearengen was an American pimp and entertainment entrepreneur who ran the Gem Theater, a notorious brothel, in Deadwood, South Dakota, for 22 years during the late 19th century.

Deadwood is a city that serves as county seat of Lawrence County, South Dakota, United States. It was named by early settlers after the dead trees found in its gulch. The city had its heyday from 1876 to 1879, after gold deposits had been discovered there, leading to the Black Hills Gold Rush. At its height, the city had a population of 25,000, attracting Old West figures such as Wyatt Earp, Calamity Jane, and Wild Bill Hickok.