On September 19, a detachment of Porter's V Corps pushed across the river at Boteler's Ford, attacked the Confederate rearguard commanded by Brigadier General William Pendleton, and captured four guns.
Early on the 20th, Porter pushed elements of two divisions across the Potomac to establish a bridgehead. Hill's division counterattacked while many of the Federals were crossing and nearly annihilated the 118th Pennsylvania (the "Corn Exchange" Regiment), inflicting 269 casualties.
This rearguard action discouraged Federal pursuit. On November 7, President Lincoln relieved McClellan of command because of his failure to follow up General Robert E Lee's retreating army.
Major General Ambrose E. Burnside rose to command the Union army.
Result(s): Confederate victory
Location: Jefferson County
Campaign: Maryland Campaign (September 1862) previous battle in campaign
Date(s): September 19-20, 1862
Principal Commanders: Major General Fitz John Porter [US]; Brigadier General William Pendleton and Major General A.P. Hill [CS]
Forces Engaged: Brigades
Estimated Casualties: 625 total