Schematic plan · American Civil War

First Battle of Bull Run

21 July 1861
Virginia
Victory for Confederacy

All battles The event in the chronicle Wikipedia

A schematic plan, generated from the statistics of the CAA Database of Battles: the armies' size and width, the hours of fighting, the plan of attack and the outcome are as recorded; the ground and the positions are not.

USA (US Army, 35,000 men under Macdowell) attacked Confederacy (Cs Army, 32,500 men under Beauregard & Johnston) in Virginia. The CAA Database of Battles records 7 hours of fighting on a front of 4.5 km, a single envelopment, left flank against hasty defense, and that Confederacy held. Losses: USA 2,896 (8%), Confederacy 1,982 (6%).

This plan is generated from those figures. It shows the shape of the battle the database describes: the size and width of the armies, the plan of attack and the outcome. It does not show where the units actually stood.

The armies

USA

Macdowell

Unit	Arm	Men
USA left wing	Infantry	8,202
USA centre	Infantry	10,936
USA right wing	Infantry	8,202
USA reserve	Infantry	6,835
USA artillery (55 guns)	Artillery	825
Macdowell	Commander	—
In this plan		35,000

Confederacy

Beauregard · Johnston

Unit	Arm	Men
Confederacy left wing	Infantry	7,312
Confederacy centre	Infantry	9,749
Confederacy right wing	Infantry	7,312
Confederacy reserve	Infantry	6,093
Confederacy cavalry of the left	Cavalry	650
Confederacy cavalry of the right	Cavalry	650
Confederacy artillery (49 guns)	Artillery	735
Beauregard & Johnston	Commander	—
In this plan		32,501

What the sources report

	USA	Confederacy
Strength, this plan	35,000	32,500
Losses, this plan	2,896	1,982

In the CAA Database of Battles

CDB90 no. 171, “First Bull Run (Manassas)”, compiled for the US Army to study what decides battles. These are the figures a what-if engine can be calibrated against.

Fighting: 7 hours
Winner: the defender
Terrain: Rolling, Mixed
Weather: Dry, Sunny, Temperate, Summer, Temperate
Defender’s posture: Hasty defense
Front width: 4.5 km (attacker), 4 km (defender)

Force	Strength	Losses	Horse	Guns	Plan and outcome
USAattacker	35,000	2,896	—	55	Single envelopment; Left flank; Repulse; Withdrew
Confederacydefender	32,500	1,982	1,300	49	Defensive/offensive plan

Attacker’s advantages none recorded

CDB90 (US Army Concepts Analysis Agency, 1990), tidy edition by Jeffrey B. Arnold; data under ODC-BY 1.0.

Notes

On this reconstruction

Generated automatically from the statistics in CDB90. Frontages, depths, distances, the order of events and the terrain are schematic: they follow the recorded strengths, front widths, hours of fighting, tactical plan and outcome, not maps or accounts of the battle. The sources give no hours; the timing is conjectural.

Sources

US Army Concepts Analysis Agency; tidy edition by Jeffrey B. Arnold, CAA Database of Battles (CDB90), no. 171 · ODC-BY-1.0Strengths, losses, front widths, hours of fighting, tactics and outcome.
Wikipedia contributors, First Battle of Bull Run · CC-BY-SA-4.0

Facts gathered from Wikidata (CC0), Wikipedia (CC BY-SA 4.0) and Wikimedia Commons (licence per file); the plan and its text are timeastra’s own.