Patrick Magruder was an American lawyer, politician, and librarian who served as a Member of the U.S. House of Representatives from Maryland’s 3rd congressional District from March 4, 1805, to March 3, 1807, and as the 2nd Librarian of the United States Congress, from December 26, 1807, to January 18, 1815.

The librarian of Congress is the head of the Library of Congress, appointed by the president of the United States with the advice and consent of the United States Senate, for a term of ten years. The librarian of Congress also appoints and oversees the Register of Copyrights of the U.S. Copyright Office and has broad responsibilities around copyright, extending to electronic resources and fair use provisions outlined in the Digital Millennium Copyright Act. The librarian determines whether particular works are subject to DMCA prohibitions regarding technological access protection. In addition, the librarian appoints the U.S. poet laureate and awards the Gershwin Prize for Popular Song.