On April 14, 1861, President Lincoln learned that Ft. Sumter had been evacuated following its bombardment by the newborn Confederacy. The Civil War had begun. On April 15, Lincoln called for the mobilization of 75,000 troops.
In the far north there was a tremendous outpouring of support, but the nation’s capital was surrounded by the states of Virginia and Maryland, where secessionist sentiment was strong.
On April 17 Virginia joined the Confederacy. On April 18 the Virginia militia took over the federal arsenal at Harpers Ferry. On April 19, a mob in Baltimore attacked the Sixth Massachusetts, on its way to defend the capital. The mob also burned the railroad bridges, isolating Washington, D.C. from the north. The mayor of Baltimore protested to Lincoln that Pennsylvania troops had been sighted as well, and this would likely incite more violence. (They would eventually get to the capital via steamers on the Chesapeake Bay.)
Monday, April 22, was “the day of the Great Exodus.” Hundreds of government workers and army officers resigned and defected to the Confederacy.
General Winfield Scott (Commander in Chief of the U.S. Army) prepared for a last ditch holdout for the President and his cabinet at the Treasury Department, complete with sandbags for the outside, and pork and beans for the inside.
On April 25, salvation came. At around noon, the Seventh New York, having taken a circuitous route through Philadelphia and Annapolis, arrived in Washington and marched down Pennsylvania Avenue to the White House. The fall of the government had been averted.