Camp Mills was a military installation on Long Island, New York. It was located about ten miles from the eastern boundary of New York City on the Hempstead Plains near Garden City.
It was named in honor of Major General Albert L. Mills, who was awarded the Medal of Honor for gallantry during the Spanish-American War. Initially it was established as a temporary tent camp in September 1917 as a place to mobilize the 42nd Division, made up of National Guard units from various states. After the 42nd left for the Western Front in France, the 41st Division followed, occupying the camp from October to November 1917. It was then ordered to be abandoned, but reestablished April 4, 1918, as a part of the Port of Embarkation at Hoboken, New Jersey for troops in transit, working as such until Armistice Day, November 11, 1918. It was then used as a point of debarkation for those returning from Europe. In 1919, the camp was ordered to be abandoned and sold, although operations continued until March 31, 1920, when garrison troops were transferred elsewhere. In 1938 Camp Mills was incorporated into Mitchel Field as part of an Air Corps expansion.
A monument to the Rainbow Division (42nd) at St James Street and Rainbow Place in Garden City near the site of Camp Mills was restored and then rededicated on November 11, 2004.