20th Massachusetts Infantry

== Regimental History and Service Record ==
Organized at Readville August 29 to September 4, 1861. Left State for Washington, D.C., September 4. Attached to Lander's Brigade, Division of the Potomac, to October, 1861. Lander's Brigade, Stone's (Sedgwick's) Division, Army of the Potomac, to March, 1862. 3rd Brigade, 2nd Division, 2nd Army Corps, Army of the Potomac, to March, 1864. 1st Brigade, 2nd Division, 2nd Army Corps, to July, 1865.
SERVICE.--Moved to Poolesville, Md., September 12-15, 1861. Guard duty along Upper Potomac until December. Operations on the Potomac October 21-24. Action at Ball's Bluff October 21. Near Edwards' Ferry October 22. Moved to Muddy Branch December 4, and duty there until March 12, 1862. Moved to Harper's Ferry, thence to Charlestown and Berryville, March 12-15. 
* Ordered to Washington, D.C., March 24
* Ordered to the Peninsula March 27. 
* March 17-September 2, 1862 - The Peninsula Campaign
** April 5-May 4, 1862 - Siege of Yorktown, Virginia
** May 7, 1862 - Engagement at Eltham's Landing, Virginia
** May 31-June 1, 1862 - Battle of Seven Pines, Virginia 
** June 25-July 1, 1862 - The Seven Days Battles before Richmond, Virginia
*** June 25, 1862 - Engagement at Oak Grove, Virginia
*** June 29, 1862 - Battle of the Peach Orchard, Virginia 
*** June 29, 1862 - Engagement at Savage's Station, Virginia
*** June 30, 1862 - Engagement at White Oak Swamp, Virginia
*** June 30, 1862 - Engagement at Glendale, Virginia
*** July 1, 1862 - Engagement at Malvern Hill, Virginia
Malvern Hill August 5. At Harrison's Landing until August 15. Movement to Alexandria August 15-28, thence march to Fairfax C. H. August 28-31. Cover retreat of Pope's army from Bull Run August 31-September 1. 
* September 3-20, 1862 - The Maryland Campaign
** South Mountain, Md., September 14 (Reserve).
** September 17, 1862 - Battle of Antietam, Maryland
Moved to Harper's Ferry September 22, and duty there until October 30. Reconnaissance to Charlestown October 16-17. Advance up Loudon Valley and movement to Falmouth, Va., October 30-November 17. Battles of Fredericksburg December 11-15. (Forlorn hope to cross Rappahannock December 11.) Duty at Falmouth until April. 
* April 27-May 6, 1863 - The Chancellorsville Campaign
Maryes Heights, Fredericksburg, May 3. Salem Heights May 3-4. 
* June 11-August 1, 1863 - The Gettysburg Campaign
** July 1-3, 1863 - Battle of Gettysburg, Pennsylvania
Advance from the Rappahannock to the Rapidan September 13-17. Bristoe Campaign October 9-22. Bristoe Station October 14, Advance to line of the Rappahannock November 7-8. Mine Run Campaign November 26-December 2. Demonstration on the Rapidan February 6-7, 1864. At Stevensburg until May. 
* May 4-June 12, 1864 - The Overland Campaign-June. 
** May 5-7, 1864 - Battle of the Wilderness, Virginia
** May 8-21, 1864 - Battles of Spotsylvania Court House, Virginia
*** May 8, 1864 - Combat at Laurel Hill, Virginia
*** May 10, 1864 - Combat at Po River, Virginia
*** May 12, 1864 - Assault on the Salient at Spotsylvania Court House, Virginia
** May 22-26, 1864 - Operations on Line of the North Anna River, Virginia
** May 26-28, 1864 - Operations on Line of the Pamunkey River, Virginia
** May 28-31, 1864 - Operations on Line of the Totopotomoy River, Virginia
** June 1-12, 1864 - Battles of Cold Harbor, Virginia
Before Petersburg June 16-18. Siege of Petersburg June 16, 1864, to April 2, 1865. Jerusalem Plank Road June 22-23, 1864. Demonstration north of the James July 27-29. Deep Bottom July 27-28. Strawberry Plains, Deep Bottom, August 14-18. Ream's Station August 25. Boydton Plank Road, Hatcher's Run, October 27-28. Dabney's Mills, Hatcher's Run, February 5-7, 1865. Watkins' House March 25. Appomattox Campaign March 28-April 9. Crow's House March 31. Fall of Petersburg April 2. Sailor's Creek April 6. High Bridge and Farmville April 7. Appomattox C. H. April 9. Surrender of Lee and his army. At Burkesville until May 2. March to Washington, D.C., May 2-15. Grand Review May 23. Duty at Washington until July 15. Mustered out July 16 and discharged July 28, 1865.
== Regimental Roster ==
== Regiment Statistical Information ==
Source 	Casualties	Remarks
Dyer 	
* 17 Officers and 243 enlisted men killed and mortally wounded 
* 1 Officer and 148 enlisted men killed by disease
* Total 409	None
Fox 	
* 17 Officers and 243 enlisted men killed and mortally wounded
* Total 263 (Combat Losses)
* Fox lists this unit as: 
** 5th on the list of units "sustaining greatest loss in action" (Infantry units with over 200 casualties)
** 68th on the list of units with losses based on duration of the entire term of service of the unit (8th of the Massachusetts troops)	
WotRWiki Statistics	
* troops killed
** Includes troops mortally wounded
** Includes troops killed by disease
** All others are troops killed in action or under special circumstances	
== Legacy ==
== Notes ==
== Sources == 
* (Pages 761, 827, 897, 899, 901, 902, 903, 904, 905, 932, 933, 934, 935, 936, 937, 938, 939, 941, 1254-1255)
* (Pages 2, 3, 4, 11)
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