On April 6, 1917, the U.S. joined its allies to fight in World War I and three months later the Coast Artillery Reserve Companies of the Washington National Guard were drafted into service. This image was taken in October 1917 as the four companies of the Seattle Battalion, Washington 63rd Coast Artillery, march to the trains that will take them to Idaho and Montana, where they did garrison duty in the Coast Defense Command. In June of 1918 they were ordered overseas, arriving in France at the end of July, and returning on March 12, 1919, once again parading in downtown Seattle.

Caption information source: https://www.mil.wa.gov/uploads/pdf/history/fields_vol_v.pdf
Caption information source: The Seattle Daily Times March 13, 1919.
Caption information also derived from captions written by Post-Intelligencer staff and attached to the back of the photograph.