Yankee Division is formed.

(Summer) Officially the Twenty-Sixth Massachusetts Regiment, the National Guard unit includes more than 30,000 men from every New England state and is led by Gens. Clarence Edwards and Edward Logan. The first American Expeditionary Force to arrive in France and engage in battle, it sees action at Belleau Wood, Chateau Thierry, St. Mihiel, and the Argonne Forest. The regiment sustains the highest casualty rate of any American unit in World War I, before returning to Boston in 1918.*