Before 1915 men wore overcoats or raincoats (aka Macs). Overcoats were warm but heavy, and raincoats were light but not warm. The advent of the Great War necessitated a solution to combine the advantages of both styles of coats for officers in the trench – thus the name Trench Coat.
Produced in khaki cotton with an oiled silk waterproof interlining, the new ‘trench’ coat was made in both single and double breasted styles, most often with a removable lining of sheepskin or blanket wool. The body was cut like a sack with a belt to adjust to the wearer’s waist, and straps on long sleeves that could be pulled tight to the wrist. Some styles had D rings attached to the belt for adding gear. Patch pockets were sewn with expanding pleats to accommodate various items, and a buttoned flap to keep the contents dry. The collar could be done up in several variations from open to buttoned to the chin, and some early designs incorporated a buttonhole slit at the front of the skirts at the hem so they could be tied back to aid marching.
The style developed in England early in the war for use by officers, and was quickly adapted for women’s service uniforms (nurses, ambulance drivers). The long coat style, as well as a shorter jacket version, were avidly worn by American soldiers soon after they started arriving in Europe in the fall of 1917. By the end of the following year, after the war, manufacturers continued making trench coats but for civilian use in tan and navy blue gabardine.