USS Margin (SP-2119), also ID-2119, was a United States Navy patrol vessel in commission from 1918 to 1919.

Margin was built as a private motorboat of the same name in 1917 by W. E. Haff at Neptune Island, New York.

On 6 December 1917, the 3rd Naval District inspected her for possible naval service, and on 21 March 1918 the U.S. Navy acquired her under a free lease from her owner, W. D. Hatch of Neptune Island, for use as a section patrol boat during World War I.

Assigned to the 4th Naval District, Margin served on patrol duty for the rest of World War I.

The Navy returned her to Hatch on 1 April 1919.