The U.S. Army surrendered Fort Sumter in the harbor Charleston, South Carolina, to Confederate forces on April 14, 1861.

[2] The next day, President Abraham Lincoln called for 75,000 volunteers to serve for 90 days to reclaim federal property and to suppress the rebellion begun by the seven Deep South states which had formed the Confederate States of America (Confederacy).

[3] Instead, political leaders in these states began the process of secession from the Union with the intent of joining the Confederacy.

[13] The 1st Michigan Infantry (90-day) was attached to Orlando Willcox's Brigade, Samuel Heintzelman's Division, Irwin McDowell's Army of Northeastern Virginia.

[12][19] It was during this operation that Colonel Ellsworth took down a secessionist flag at the Marshall House hotel and was killed by its proprietor James W.

[24] Major General Robert E. Lee, commanding the state forces, issued an order in compliance with the proclamation on June 8.

[25] Companies from both the 1st Michigan Infantry under Captain Brown and the 11th New York Infantry under Captain Roth performed picket duty and camped at Arlington Mills (or Arlington Mill as later named), Virginia, about 5 mi (8.0 km) from the Long Bridge at Washington.

[30] At about 11:00 p.m., nine Virginia militia men, according to contemporary accounts, fired a volley on the Union sentinels.

[30] At least one newspaper reported that in the confusion the Michigan men and the New York Zouaves fired on each other as well as at the Virginia soldiers.

[26][30][31] The web site of a re-enactor group as well as William S. Connery's book state with respect to the picket duty performed by the regiment in the early days of the war: "21-year-old Henry S. Cornell of Company G, a member of Engine Co. 13, was killed and another man wounded one night on the picket line.

"[15][30] Following the Battle of Fairfax Court House and the skirmish at Arlington Mills on the same day, the Union Army did not attempt to move farther into northern Virginia until June 17, when a Union reconnaissance in force led to the Battle of Vienna, Virginia.

[37] In 2011, Arlington County, Virginia began work on a new community center to replace one just demolished on the site.