Gules, two chevronels between the sails of an old Dutch windmill in dexter chief, a lightning bolt in sinister chief and in base a fleur-de-lis, all Or.
That for the regiments and separate battalions of the Army Reserve: On a wreath of the colors, Or and Gules, the Lexington Minute Man Proper. The statue of the Minute Man, Captain John Parker (H.H. Kitson, sculptor) stands on the Common in Lexington, Massachusetts.
OUR UTMOST ALWAYS.
The shield is red for Artillery. The windmill is taken from the coat of arms of New York, the state to which the regiment was allocated after World War I and is also the shoulder sleeve insignia of the Corps in which the regiment belonged. The lightning bolt is taken from the shoulder sleeve insignia of the 78th Division in which the regiment was originally organized. The fleur-de-lis is in memory of the regiment's service in France. The chevronels are the English heraldic sign of roof rafters indicating welcome and hospitality. The motto is an adaptation of a phrase used by the Colonel commanding the regiment on the eve of his departure for France.
The crest is that of the U.S. Army Reserve.
The coat of arms was originally approved for the 309th Field Artillery Regiment, Organized Reserves, on 27 June 1925. It was redesignated for the 309th Field Artillery Battalion on 25 August 1942. The insignia was rescinded effective 20 April 1960.