Source: https://dmna.ny.gov/nyg/?id=history

On 3 August 1917, the Adjutant General of New York, in order to comply with the provisions of the State Constitution requiring that troops be available to the Governor for the protection of life and property of the citizens of New York, organized a State Military Force known as the New York Guard. The new force replaced the New York National Guard, drafted in the service of the United States on 5 August 1917.

Additionally, in accordance with Special Orders No. 311, Adjutant General’s Office dated 11 December 1917 a Provisional Brigade of the New York Guard was created from existing units, to include a Brigade Headquarters and the 1st and 2nd Provisional Regiments which were ordered to active duty guarding public property. The Headquarters of the Brigade was located at Albany, New York. The 1st Provisional Regiment Headquarters first located at Croton Lake and later at Ossining, New York, had the mission of guarding the water supply of the City of New York, Ashokan OP4 with its territory extending from the northern boundary of the city to include the entire Croton Aqueduct system. The territory assigned to the 2nd Provisional Regiment extended from Troy and Albany across the State to the International Border at Niagara Falls. The Headquarters of the 2nd Provisional Regiment was located in the State Armory, Troy, New York.

During the existence of the Provisional Brigade, a total of 9,960 men were ordered on active duty. Discipline was maintained by enforcement of Articles of War, State Military Law & Regulations. On 1 January 1919, the strength of the NYG was approximately 22,000 officers and men.

After the Armistice was signed and the Federalized New York National Guard units were returned to State status, New York Guard units were deactivated.