Patrick Magruder (1768 – December 24, 1819) was the second U.S. Librarian of Congress, serving from 1807 to 1815.

Magruder was born at "Locust Grove", his family’s estate near Rockville in Montgomery County, Maryland. Magruder attended Princeton College and became a lawyer. In 1805, he was elected to the Ninth United States Congress from Maryland. After the death of John J. Beckley, President Jefferson appointed Magruder to the dual post of Clerk of the United States House of Representatives and Librarian of Congress. (The posts were not separated until 1815.) During the War of 1812, the British burned Washington D.C., including the Library of Congress, which was then housed in the US Capitol Building. After a investigation by Congress into the destruction of the Library and the use of Library funds, Magruder resigned. He was buried on his family’s ancestral estate, "Sweden," near Petersburg in Dinwiddie County, Virginia.