This unique garrison cap and souvenir flag once belonged to a member of a US 322nd Field Artillery regiment veteran's organization. I am unsure of the exact date, but was able to find images of an official roster published in 1956 which features the exact same logo and was published at the HQ in Hamilton, Ohio. 
 
The 322nd Field Artillery received basic training at Camp Sherman in Ohio and saw service in Europe during World War I. After the war, the 322nd was assigned to the 32nd Division as part of the Army of Occupation. The regiment remained in Germany until April 1919, when it was ordered home.The first annual reunion was held at Dayton, Ohio in 1920. After sixty-two reunions, the 322nd Field Artillery Association closed its books for the final time in 1981. It was the oldest continuing reunion of a military unit in the United States.