To this day, the most provocative public symbol in the state of Montana is a set of numbers — 3-7-77 — whose meaning is a complete and utter mystery to everyone living there.
The mysterious numbers 3-7-77, often posted on doors, were used for years as a symbol of banishment in Montana. But contrary to widespread belief, they were never used by the original vigilantes of 1864 who hanged Sheriff Henry Plummer. The numbers actually appeared for the first time in 1879 to warn "undesirables" to leave Helena. Today the numbers appear on the shoulder patch and car door insignia of the Montana Highway Patrol and are meant to convey a benign message of law and order. Montana Vigilantes