Hat cords are associated with Campaign Hats, the domed headgear worn by Army Drill Sergeants, Marine Crops Drill Instructors, and Coast Guard Company Commanders at Training Center Cape May. Introduced in the Army in 1872, they were worn until the end of World War II, when they were phased out for roughly twenty years before being brought back for wear by Drill Sergeants because it was viewed as a symbol of a tradition of expertise and experience.
But a strange thing happens when you scour old Army uniform regulations for information on Campaign Hats and the colored hat cords worn with them: you won’t find them mentioned. That’s because they were referred to by other names that we today typically associate with a different type of headgear. Published in 1942, AR 600-35, Prescribed Service Uniform, designates them as “Hat, Service,” but the description leaves no doubt as to what they look like: “A standard adopted design with ‘Montana peak,’ four indentations, crown 5-1/2 inches high for size 7-1/8, with an olive-drab band and bow 15/16-inch in width.”
In paragraph 23-24, section c(4) of that manual, the cord for the hat is prescribed as a “double cord of the color of the arm, service, or bureau.” At that time, Yellow was the color of Cavalry, but after Armor adopted the color in 1951 it has been used for both Cavalry and Armor units. Probably the Cavalry hat cord most people are familiar with is the one on the “Cavalry Stetson” or “Cav hat” worn by Robert Duvall as Lieutenant Colonel William Kilgore in the Vietnam War film epic Apocalypse Now.