 Although the feud was originally fought between the Tewksburys and the Grahams against the well-established cattleman James Stinson, it soon involved other cattlemen associations, sheepmen, hired guns, cowboys and Arizona lawmen.The feud lasted for about a decade, with its most deadly incidents between 1886 and 1887; the last-known killing took place in 1892.The Pleasant Valley War had the highest number of fatalities of such range conflicts in United States history, with an estimated total of 35 to 50 deaths, and the near annihilation of the males of the two feuding families.