Located at 65 Mitchell Place/35 South Broadway, the building was built to serve as a National Guardarmory.[2] Construction of the building began in 1909 and was completed in 1910.[2] The building was designed by architect James E. Ware.[2] The building was 31,612 square feet and takes up three-quarters of an acre.[2] 49th Separate Company/Company L, 10th Infantry Regiment occupied the armory from 1910 to 1939.[2] From April 1924 to November 1929, the White Plains Armory was the temporary headquarters of Troop K of the New York State Police, after a March 3, 1924 fire destroyed the troop's headquarters at Gedney Farms.[3] The police troop left the Armory in November 1929 after a new headquarters in Hawthorne was completed.[3]
Subsequently, the building's tenants were the 106th Infantry Regiment and then the Headquarters and Headquarters Battalion, Company D, 212th Field Artillery.[2]