The days of Maryand and Delaware being considered Southern states are over. Hard to believe that Washington DC was once considered a Southern city. But it was.
Maryland has always been a divided state. Western Maryland (west of the Chesapeake Bay and joining Pennsylvania) fought for the North. The Eastern Shore, (East of the Chesapeake Bay) fought in the Army of Northern Virginia under Lee. Maryland would have seceded from the union, however, Lincoln had a female spy who reported a planned meeting to secede. On the given date, Lee dispatched Federal Troops to arrest the representatives of the people so they could not leave the union. Washington, D.C. is built on Maryland soil. Had Maryland seceded, Washington would have been easily overrun.