April 20, 1937
Gov. E.W. Marland signed legislation establishing a state police force, which would come to be known as the Oklahoma Highway Patrol.
May 7, 1941
Trooper Sam R. Henderson became the first Oklahoma Highway patrolman to die in the line of duty. Henderson was hit by a passing car while talking to the driver of a vehicle he had stopped near Lawton. A drunken soldier from Fort Sill was driving the car that hit him.
World War II depletes the patrol's manpower, with a force of 150 troopers cut to less than 50 as many were either drafted or enlisted in the armed forces. An auxiliary force of civilians helped fill the gap during the war by investigating accidents and serving as dispatchers for the few troopers who remained.
The patrol becomes the first law enforcement agency in the country to use aircraft for traffic control.