On this day 150 years ago, a signals officer sent this terse telegram to Union Major General Henry W. Slocum, communicating the news that the Army of Northern Virginia was crossing the Potomac into Maryland in force. At this time, Slocum was commander of the Union XII Corp, part of the Army of the Potomac.
MARYLAND HEIGHTS SIGNAL STATION,
June 24-10. 40 a. m.
Large trains are crossing at Sharpsburg. Artillery and general trains are passing near Charlestown toward Shepherdstown.
Lieutenant, Signal Officer.