Battle of Ball's Bluff order of battle: Union

The following Union Army units and commanders fought in the Battle of Ball's Bluff of the American Civil War, fought from October 20 to October 24, 1861, in Loudoun County, Virginia, also known as the Battle of Leesburg or the Battle of Harrison's Island. The Confederate order of battle is shown separately.

Abbreviations used

Division	Brigade	Regiments and Others
Stones' Division^[1] (Corps of Observation) BG Charles Pomeroy Stone	First Brigade BG Frederick W. Lander	1st Company Massachusetts Sharpshooters: Cpt John Saunders^[2] 7th Michigan Infantry: Col Ira Grosvenor 19th Massachusetts Infantry: Col Edward Hinks 20th Massachusetts Infantry: Col William Raymond Lee (c)
	Second Brigade BG Willis A. Gorman	1st Minnesota Infantry: Col Napoleon J.T. Dana 2nd New York State Militia: Col George W.B. Tompkins 34th New York Infantry: Col William LeDew
	Third Brigade Col Edward D. Baker (k)	1st California Infantry: Ltc Isaac J. Wistar (w) 2nd California Infantry: Col Joshua T. Owen 3rd California Infantry: Col DeWitt C. Baxter 5th California Infantry: Col Turner G. Morehead
	Unassigned Regiments	15th Massachusetts Infantry: Col Charles Devens (w) 42nd New York Infantry (Tammany Jackson Guard): Col Milton Cogswell (w&c)
	Cavalry	3rd New York Cavalry Regiment (B, D, E, and I companies): Col James Henry Van Alen Putnam Rangers, D.C. Volunteer Cavalry: Cpt George Thistleton
	Artillery	1st U.S. Artillery, Battery I: Lt George A. Woodruff 1st Rhode Island Light Artillery, Battery B: Cpt Thomas F. Vaughn 2nd New York State Militia Artillery Detachment 6th New York Independent Battery: Cpt Thomas B. Bunting

Morgan, James A. III (2004). A Little Short of Boats: The Fights at Ball's Bluff and Edwards Ferry, October 21–22, 1862; a history and tour guide. Discovering Civil War America. Vol. 2. Fort Mitchell, Kentucky: Ironclad Publishing. pp. 225–228. ISBN 0-9673770-4-8.

^ The "Official Records" and most secondary sources like Dyer's Compendium reverse the listing of Lander's and Gorman's brigades, assign the 15th Massachusetts and 42nd New York to Gorman's brigade, and do not include the Putnam Rangers as part of General Stone's attached cavalry. The information above, however, was taken from Record Group 393 (Corps of Observation Records, National Archives, Washington, DC) which contains the actual orders and correspondence of Stone's division.
^ Ellis, Alden C. (2012). The Massachusetts Andrew Sharpshooters. US: McFarland. p. 96. ISBN 978-0-7864-6489-0. Archived from the original on 2012-05-09. Retrieved 2012-07-05.