Philip St. George Cocke (April 17, 1809 – December 26, 1861) was a brigadier general in the Confederate States Army during the first year of the American Civil War. He is best known for organizing the defense of Virginia along the Potomac River soon after the state's secession from the Union. He commanded troops in the Battle of Blackburn's Ford and the First Battle of Bull Run (First Manassas) in July 1861 before becoming despondent and committing suicide.