In the late 60s "mainstream" country music had settled into two set formulas - one had full orchesteral backing (violins and all) and the other was pure "get drunk/cry in your beer" honky tonk. Several artists and composers were frustrated and wanted to go in a different (younger) direction. This became the "Outlaw" movement. The term outlaw referred to their not wanting to go along with the way Nashville was doing things. Waylon Jennings really set in motion when he demanded and got full control of all aspects of his record production. Soon, whole new studios, and labels were born.
In addition to Waylon and Willie Nelson (the most visible "Outlaws") were Johnny Cash, Merle Haggard, David Allan Coe, Tompall Glazer, Kris Kristofferson, Billy Joe Shaver, Leon Russell, and Hank Williams, Jr. Butch Hancock, Joe Ely, and Jimmie Dale Gilmore (The Flatlanders) were doing their own thing in Austin, Texas and several of the others joined them there.