This museum is set in the old Teller County Jail, which rather remarkably operated from 1901 all the way until 1992 when the ACLU filed the lawsuit that made them upgrade. You'll be able to explore the tiny 6.5ft-by-9ft cells that held six men each. The men slept on hammocks, practically on top of one another. There's even a solitary confinement cell where one of the Wild Bunch was held briefly.
Other than him, there were no particularly famous outlaws or sheriffs in the area, but the museum does have displays of old news stories from turn-of-the-century local papers: the Morning Times-Citizen and Castle Rock Journal.