4th Pennsylvania Reserve Regiment

4th Pennsylvania Reserve Regiment
Pennsylvania flag, c. 1863
Active	July 17, 1861 – June 8, 1864
Country	United States
Allegiance	Union
Branch	Infantry
Engagements	Battle of Mechanicsville Battle of Gaines' Mill Battle of Glendale Battle of Malvern Hill Battle of Second Bull Run Battle of South Mountain Battle of Antietam Battle of Fredericksburg Battle of Cloyd's Mountain

The 4th Pennsylvania Reserve Regiment, also known as the 33rd Pennsylvania Volunteer Infantry Regiment, was an infantry regiment that served in the Union Army during the American Civil War. It was a part of the famed Pennsylvania Reserves in the Army of the Potomac for much of the early part of the war and served in the Eastern Theater in several important battles, including Antietam and Fredericksburg.