John Peters Ringo, known as Johnny Ringo, was an American Old West outlaw loosely associated with the Cochise County Cowboys in frontier boomtown Tombstone, Arizona Territory. He took part in the Mason County War in Texas during which he committed his first murder. He was arrested and charged with murder. He was affiliated with Cochise County Sheriff Johnny Behan, Ike Clanton, and Frank Stilwell during 1881–1882. He got into a confrontation in Tombstone with Doc Holliday and was suspected by Wyatt Earp of having taken part in the attempted murder of Virgil Earp and the ambush and death of Morgan Earp. Ringo was found dead with a bullet wound to his temple which was ruled a suicide. Modern writers have advanced various theories attributing his death to Wyatt Earp, Doc Holliday, Frank Leslie or Michael O'Rourke.

Mason County is a rural county located on the Edwards Plateau in the U.S. state of Texas. At the 2020 census, its population was 3,953. Its county seat is Mason. The county is named for Fort Mason, which was located in the county.