The Hole-in-the-Wall Gang was a gang in the American Wild West, which took its name from the Hole-in-the-Wall Pass in Johnson County, Wyoming, where several outlaw gangs had their hideouts. The Gang was not simply one large organized gang of outlaws, but rather was made up of several separate gangs, all operating out of the Hole-in-the-Wall Pass, using it as their base of operations. The gangs formed a coalition, each planning and carrying out its own robberies with very little interaction with the other gangs. At times, members of one gang would ride along with other gangs, but usually each gang operated separately, meeting up only when they were each at the hideout at the same time.
Geographically, the hideout had all the advantages needed for a gang attempting to evade the authorities. It was easily defended, and impossible for lawmen to access without detection by the outlaws concealed there. It contained an infrastructure, with each gang supplying its own food and livestock supply, as well as its own horses. A corral, livery stable, and numerous cabins were constructed, one or two for each gang. Anyone operating out of there adhered to certain rules of the camp, to include a certain way in handling disputes with other gang members, and never stealing from another gang's supplies, and there was no leader, with each gang adhering to its own chain of command. The hideout was also used for shelter and a place for the outlaws to lay up during the harsh Wyoming winters.
Members included such infamous desperadoes as Butch Cassidy, the Sundance Kid, Kid Curry and his brother Lonny Curry, "Laughing" Sam Carey, Black Jack Ketchum, Elzy Lay, and George "Flat Nose" Curry, along with several lesser known outlaw gangs of the Old West. Several posses trailed outlaws to the location, and there were several shootouts as posses attempted to enter, all resulting in the posses being repulsed, and being forced to withdraw. No lawmen ever successfully entered it to capture outlaws during its more than fifty years of active existence, nor were any lawmen attempting to infiltrate it by use of undercover techniques successful.
The encampment operated with a steady stream of outlaw gangs rotating in and out from the late 1860s to the early 20th century. However by 1910, very few outlaws used the hideout, and it eventually faded into history. One of the cabins used by Butch Cassidy still exists today, and was relocated to Cody, Wyoming, where it is on display to the public.