Montana's last hanging was September 10, 1943. The state's last hanging in Missoula in 1943 was also the state's last execution for 52 years. Montana didn't execute another inmate until 1995, when Duncan McKenzie was executed by lethal injection after spending 20 years on death row. Today, lethal injection is the only death sentence method allowed in the state, and McKenzie's execution was the last time it was used.