During the Antietam Campaign, the U.S. Signal Corps used the stone structure on this mountain as a signal station. On July 4, 1827, citizens of Boonsboro paraded to the mountaintop and began building the first monument in the country completed in honor of George Washington. On September 14, 1862, during the Battle of South Mountain, as Confederate Gen. Robert E. Lee and his staff entered Boonsboro, Lt. Col. E.P. Alexander saw a small party on the tower and, thinking they were Union signalers, led eight men up to investigate, only to find local citizens trying to get a better view of the fighting. Federal signalmen later used the monument, including during the Battle of Antietam three days afterward. In 1863, during the Confederate retreat after the Battle of Gettysburg, the two armies returned to this valley and fought across Washington County from July 5 to 14 at Boonsboro, Funkstown, and Hagerstown.
