The Lincoln County War was the 1878 conflict between rival cattle factions and their supporters in Lincoln County, New Mexico Territory.
The dispute began after the murder of merchant John Tunstall on February 18, 1878. Tunstall’s employees and allies formed the Regulators, while supporters of the established Murphy-Dolan faction organized against them.
The conflict involved ambushes, raids, and competing claims to legal authority. Billy the Kid became associated with the Regulators, although the struggle involved many other ranchers, businessmen, deputies, and gunmen.
The war’s most important confrontation occurred during the Battle of Lincoln in July 1878. Federal troops intervened, helping end the open fighting, but the underlying political and economic rivalries continued. The Lincoln County War is separate from Wyoming’s 1892 Johnson County War, another range conflict involving cattle interests.