It is September 3, 1862.

In two weeks, Confederate and Union forces will clash in the fields of southern Maryland along a creek called Antietam.

Tomorrow, September 4, Confederate Col. Robert E. Lee's army will begin crossing the Potomac River and entering Maryland, bringing the Civil War into Union territory for the first time.

The South is ascendant.

The Confederate summer offensive yielded several battlefield victories, including Lee’s victory at Manassas, Virginia, just thirty miles west of Washington, last week.

Defeated Union forces have retreated to Washington, D.C., and are said to be demoralized.

Get full access to Photo of the Day at look.substack.com/subscribe