Established by Act of Congress on August 30, 1890, this Civil War site marks the end of General Robert E. Lee's first invasion of the North in September 1862. The battle claimed more than 23,000 men killed, wounded, and missing in one single day, September 17,1862, and led to Lincoln's issuance of the Emancipation Proclamation.

Housed in a 1849 train station, the museum features a permanent exhibition that addresses Baltimore during the Civil War and the part that the President Street Station played in this era, Maryland's railroad history and the building's role in the transportation of slaves escaping to the North.

Antietam National Cemetery is one of the 130 cemeteries of the National Cemetery System, a system that began during the Civil War. There are 4,776 Union remains (1,836 or 38% are unknown) buried here from the Battle of Antietam, South Mountain, Monocacy, and other action in Maryland. All of the unknowns are marked with small square stones. These stones contain the grave number, and if you look closely on a few stones, a small second number represents how many unknowns are buried in that grave. There are also a few of the larger, traditional stones that mark unknown graves. In addition, more than 200 non-Civil War dead are also buried here. Veterans and their wives from the Spanish-American War, World War I and II, and Korea were also buried here until the cemetery closed in 1953.

Eight miles downriver from the capital, Fort Foote was considered "a powerful enclosed work" by its chief engineer, "and the most elaborate...of all the defenses of Washington." The long oval earthwork was constructed on Rozier's Bluff from 1863 to 1865 to strengthen the ring of fortifications that encircled Washington, D.C., during the Civil War. Fort Foote was designed to protect the river entrance to the ports of Alexandria, Georgetown, and Washington and replace the aging Fort Washington as the primary river defense. The fort was named for Rear Adm. Andrew H. Foote who died in 1863 from wounds he received in combat the previous year. Over the massive rammed-earth parapets, two 15-inch Rodman guns and four 200-pounder rifled Parrotts had muzzles trained down the Potomac River. With a deafening roar, the Rodman cannon could hurl 440-pound shells for three miles. Siege and field guns were stationed to fire on any party attacking from land. Companies of the 9th New York Heavy artillery worked to build and arm the fort. The last in the ring of forts and batteries to be abandoned when peacetime returned, Fort Foote continued in active status until 1878. It was briefly reactivated as a training site during World War I. Today the National Park Service has cleared paths around the ruins of what is considered the best preserved Civil War fort in the region. Remounted on carriages, two Rodman guns loom in shadows under the trees, the river still in their sights.

Known as the "Battle That Saved Washington", the battle of Monocacy on July 9, 1864 between 18,000 Confederate forces under General Jubal Early, and 5,800 Union forces under General Lew Wallace, marked the last campaign of the Confederacy to carry the war into the north. One of the objectives of this campaign was to capture Washington, D.C. Although this battle was a military victory for the Confederates, it was also a defeat. Time spent for battle cost the Confederates a day's delay in marching on the federal capital. General Lew Wallace's defense along the Monocacy bought critical time to allow Washington to be reinforced. Early's raid would be thwarted and the war would be taken to the south for the rest of the war.