James Augustin Greer[1] (February 28, 1833 – June 17, 1904) was a rear admiral in the United States Navy, who served during the Civil War.

Greer was promoted to lieutenant commander[3] and served on the St. Louis from 1862 to 1863, and then was attached to Rear Admiral David Dixon Porter's Mississippi Squadron.

While in command of the ironclads Carondelet and Benton, he participated in the Vicksburg campaign and the shelling of Grand Gulf as well as the abortive Union Red River expedition[2] in early 1864.

[2] In 1866 he was elected a companion of the Pennsylvania Commandery of the Military Order of the Loyal Legion of the United States (MOLLUS).

Admiral Greer died in Washington, D.C., on June 17, 1904,[2][4] and was buried with full military honors in Arlington National Cemetery two days later.