April 17- The Virginia State Convention votes for secession. That same day James W. Jackson flies a large rebel flag over the Marshall Hotel in Alexandria which can be seen can be seen from the White House and receives considerable attention in local newspapers.

May 23- Virginia voters approve an ordinance of secession.

Full text- To repeal the ratification of the Constitution of the United States of America, by the State of Virginia, and to resume all the rights and powers granted under said Constitution. The people of Virginia, in their ratification of the Constitution of the United States of America, adopted by them in Convention, on the twenty-fifth day of June in the year of our Lord, one thousand seven hundred and eighty-eight, having declared that the powers granted under the said Constitution, were derived from the people of the United States, and might be resumed whensoever the same should be perverted to their injury and oppression; and the Federal Government having perverted said powers, not only to the injury of the people of Virginia, but to the oppression of the Southern slaveholding States. Now, therefore, we the people of Virginia, do declare and ordain that the ordinance adopted by the people of this State in Convention, on the twenty-fifth day of June, in the year of our Lord one thousand seven hundred and eighty eight, whereby the Constitution of the United States of America was ratified; and all acts of the General Assembly of this State ratifying or adopting amendments to said Constitution, are hereby repealed and abrogated; that the Union between the State of Virginia and the other States under the Constitution aforesaid is hereby dissolved, and that the State of Virginia is in the full possession and exercise of all the rights of sovereignty, which belong and appertain to a free and independent State. And they do further declare, that said Constitution of the United States of America is no longer binding on any of the Citizens of this State. This ordinance shall take effect and be an act of this day when ratified by a majority of the votes of the people of this State, cast at a poll to be taken thereon, on the fourth Thursday in May next, in pursuance of a Schedule hereafter to be enacted Done in Convention in the City of Richmond, on the seventeenth day of April, in the year of our Lord one thousand eight hundred and sixty-one, and in the eighty-fifth year of the Commonwealth of Virginia.

May 24- The Union moves to secure areas just across the Potomac in Virginia at Arlington Heights and in Alexandria. Brigadier General Joseph Mansfield, born in New Haven, Connecticut, commander of the Department of Washington, formulated a plan to invade Arlington Heights and Alexandria in order to secure Washington city. The concern was that a few well-placed batteries on Arlington Heights could easily fire on any Government building including the Capitol and the White House.

In addition, batteries near Alexandria could also shut down shipping along the Potomac River into Washington. I can’t find a report in the Official Records from General Mansfield describing the events of the invasion on May 24th, but the plan was described in reports from Charles Sanford and Samuel Heintzelman (OR pages 37-42 Volume 2 Chapter IX). At 2:00 AM three separate columns would cross the Potomac River. The first column crossed at the Georgetown Aqueduct under Captain W.H. Wood commanding the 69th NY, 5th NY, the 28th NY, one company of cavalry, one section of artillery, along with engineers and pioneers.

The second crossed at the Long Bridge under Colonel Heintzelman commanding the 7th NY, 12th NY, 25th NY, 7th NJ, and 1st MI, along with cavalry, artillery and pioneers.

The third column, consisting of the 1st NY Fire Zouaves commanded by Colonel Elmer Ellsworth, encamped on the Potomac below Eastern Branch and traveled by water to the Alexandria wharves. The 1st MI would cross at Long Bridge but would move toward Alexandria to aid the 1st NY. The crossings and occupations of Alexandria and Arlington Heights were essentially unopposed. Union forces then established outposts along roads leading to Washington through Alexandria and Arlington and began building the initial fortifications to protect them.

May 24- The occupation of Arlington Heights. General Sandford would find only servants at the Arlington House, the family had left, which would become General Mansfield’s headquarters.

May 24- Union forces invade Alexandria. Colonel Elmer Ellsworth becomes the first Union officer killed in the Civil War (link).

May 27- Private Peyton Anderson Jr. becomes the first Confederate soldier wounded in the Civil War. Anderson was a member of the Virginia Partisan Rangers and Co. B, 6th Virginia Cavalry. He enlisted on April 22, 1861, and was mustered out on January 8, 1862. He was the first Confederate soldier wounded in the Civil War while on picket duty north of Fairfax Court House. The Confederates were in possession of Fairfax Court House and Peyton Anderson and William Lillard of the 6th Virginia Cavalry were stationed about two miles from the town, on lookout for Union soldiers. A squad of Union Cavalry surrounded them, and Anderson was shot through the arm. His fellow picket William Lillard was captured. Anderson is buried in Amissville on private property in the Anderson Family Cemetery (38.6931944, -78.0772500). A monument memorializing this event was removed from Fairfax Boulevard in 2020. The incident occurred near the location of the removed monument- 38.8642667, -77.2796167.

May 29- June 1- The Battles of Aquia Landing qand Mathias Point (link). The first combat action involving the U.S. Navy in the Civil War.

May 31, 1861– As the Union pushed out into Northern Virginia Confederate President Jefferson Davis decided he needed to replace Brigadier General Milledge Luke Bonham as overall commander in Northern Virginia. He met with Brigadier General P.G.T. Beauregard. The meeting took place in Richmond, the new Confederate capital, which had moved from Montgomery, Alabama the previous day. Davis intent on protecting Richmond, informed Beauregard that he would replace Bonham as commander of the troops in Northern Virginia. After the meeting, Davis instructed General Robert E. Lee to issue Special Orders, No. 149, on May 31, 1861, assigning Beauregard “to the command of the troops in the Alexandria line.” Beauregard promptly traveled to Manassas Junction and relieved Bonham of his command on June 2, 1861. On June 20, 1861, Beauregard issued General Orders, No. 20, organizing troops under his command into six brigades that he referred to as the “First Corps, Army of the Potomac,” marking the inception of the designation “Army of the Potomac.”

June 1- Battle of Fairfax Court House (link)– The first land engagement of the Civil War that resulted in its first combat-related fatalities, the first wounding of a field-grade officer, and 32 years later the awarding of a Medal of Honor for the first action in combat of the Civil War.

June 1- Skirmish at Arlington Mills (link)

June 17- Action at Vienna (link)- the first time a railroad battle was fought in the Civil War, along with a link to other Civil War sites in Vienna.

June 24- Balloon Reconnaissance at Taylor’s Tavern (Seven Corners) (Link)- Thaddeus Lowe performed aerial reconnaissance for the Union Army in his gas filled balloon. The first time this tactic was employed in warfare in American history.

Sources

The Glories of War, Small Battles and Early Heroes of 1861 by Charles P. Poland Jr.

Chronology of the Civil War in Fairfax County Part I by Edward T. Wenzel.

A Virginia Village Goes to War, Falls Church During the Civil War by Bradley E. Gernand

Civil War Northern Virginia 1861 by William S. Connery

Actions on May 24th- OR pages 37-42 Volume 2 Chapter IX