During World War I, a military training camp was established on the Hempstead Plains. This camp was named for General Albert L. Mills who was awarded the Med of Honor for his bravery at the Battle of San Juan Hill.
Camp Mills was going to be part of an overall plan for the military on the Hempstead Plains. At the time, the Plains already had two military aviation fields. At the start of the war, the Army took over the Hempstead Plains Aerodome and renamed it Hazelhurst Aviation Field No. 1.
On August 15, 1917, the 69th New York Infantry of the National Guard were given orders to report to Camp Mills to be part of a new Rainbow Brigade. This 1,000 man regiment would be joined by other New York regiments at the Camp. A few days earlier, workmen began building more than two thousand frames and assembling tents, digging trenches, laying water pipes, preparing a drainage system, making roads, and building other necessary structures.
By August 16, Company S of the 22nd US Infantry arrived as the first contingent of troops at the Camp. When the 69th New York was placed under the control of the US Army and re-designated the 165th Infantry of the 42nd Division, it was required to add more numbers. The National Guard regiments from Manhattan and Brooklyn were ordered to transfer a designated number of men to the new Regiment. The order did not go over well with the Brooklyn Regiments. More than 300 Brooklyn solders deserted Camp Mills and returned to Brooklyn. Within a few weeks, all 300 returned without anyone going to jail.
The troops enjoyed many diversions while training at the Camp. There were boxing matches, concerts, and an exhibition game between the New York Giants and Chicago White Sox. There were a series of incidents when the troops from Alabama threw insults at the African-American 15th NY Regiment. For their protection, these men were moved to the 69th Regiment’s Armory in New York.
By early December, Camp Mills became unbearable. Winter storms, leaky tents, muddy and flooded streets, and no adequate training made life there miserable. On December 13, a blizzard hit; requiring some soldiers to be dug out from beneath their collapsed tents. By January 1918, most of Camp Mills was abandoned. In March, the War Department ordered the repair and grading of the fields, planning the roads, and improving the water system. Permanent structures began being built in April. More than twenty thousand troops occupied the camp at this time. In August 1918, the Army leased an additional 75 acres from surrounding Garden City residents and the government spent $10 million to build additional barracks and other structures.
When the war ended, Camp Mills became a demobilization camp through August, 1919. By November of 1919, many of the buildings were sold off. It was abandoned as an active post in 1920 and absorbed into Mitchel Field.
McKenna, James M. “Nassau County's Camp Mills in the Great War, 1917-1918.” The Nassau County Historical Society Journal, vol. 73, 2018, pp. 26–37