The brigades of Sidney Burbank and Hannibal Day, part of the Union 5th Corps had the distinction of being the only infantry units in the Army of the Potomac that consisted of regular U.S soldiers. For these men, being a soldier was their career and, as a result, they were highly disciplined and professional and, late in the afternoon of July 2nd, they would need every bit of those two qualities as they advanced to confront the final Confederate surge through the Wheatfield. Their fight would be brief, confusing , but very bloody. In fact, Burbank’s Brigade would end up suffering the highest casualties of any other brigade in the hard pressed 5th Corps that afternoon. We will review the role of the regulars in the Army of the Potomac leading up to Gettysburg and then discuss what happened to them on that terrible afternoon of July 2nd was they fought their way out what became a “semicircle of fire”. We will meet at the monument to Walcott’s battery at the intersection of Crawford Avenue and the Wheatfield Road.