Organized at Baltimore and Williamsport, Md., Pittsburg, Pa., and Washington, D. C., August, 1861, to June, 1862. Companies "A," "B," "C," "D," and "F" organized at Baltimore, Md. Company "G" organized at Pittsburg, Pa., as Patterson's Union Cavalry April 5, 1861. Companies "H" and "I" organized in Washington and Allegheny Counties, Pa. Company "K" organized at Allegheny City, Pa., as Morehead's Cavalry Company August 19, 1861. Companies "L" and "M" organized at Washington, D. C., May, 1862. Companies "G," "H," "I" and "K" were attached to 1st Virginia Union Cavalry August, 1861, to January, 1862, when assigned to 1st Maryland Cavalry. Regiment attached to Dix's Command, Baltimore, Md., to March, 1862 (Cos. "A," "B," "C," "D," "E" and "F"). Department of West Virginia to March, 1862 (Cos. "G," "H," "I," "K"). (Co. "K" ordered to Washington, D. C., August 19, 1861. Attached to Landers' Command, Army of the Potomac, to March, 1862. Duty at Williamsport, Hancock and Cumberland, Md.) Hatch's Cavalry Brigade, Dept. of the Shenandoah, to June, 1862. Cavalry Brigade, 2nd Corps, Pope's Army of Virginia, to September, 1862. Cavalry Brigade, 11th Army Corps, Army of the Potomac, to February, 1863. Defences Upper Potomac, 8th Army Corps, Middle Department, February, 1863. 2nd Brigade, 3rd Division, Cavalry Corps, Army of the Potomac, to June, 1863. 1st Brigade, 2nd Division, Cavalry Corps, to October, 1863. Provost Marshal General's Command, Army of the Potomac, to February, 1864. 3rd Separate Brigade, 8th Army Corps, Middle Dept., to June, 1864. 3rd Brigade, 1st Division, 10th Army Corps, Army of the James, Dept. of Virginia and North Carolina, to October, 1864. 3rd Brigade, Cavalry Division, Dept. of Virginia and North Carolina, to April, 1865. Cavalry, Dept. of Virginia, to August, 1865.

SERVICE:
Skirmishes at Edward's Ferry September 3-4, 1861 (Co. "K"). Action at Greenbrier, W. Va., October 3, 1861 (Co. "G"). Ball's Bluff, Va., October 21, 1861 (Detachment). Stone's Cross Roads, Ball's Bluff, Bath and Alpine Station, January 4, 1862 (Cos. "G," "H" and "I"). Hancock January 5-6 (Co. "K"). Bloomery Gap January 7 and February 14 (Co. "I"). Regiment at Baltimore, Md., till March, 1862. Operations in Shenandoah Valley March to June. Advance on Winchester March 7-15. Pursuit of Jackson up the Valley. Retreat to Williamsport, Md., May 24-26. Middletown May 24 (Cos. "A," "B," "C," "G" and "I"). (Cos. "D," "F," "H," "K" and "L" arrive at Harper's Ferry, W. Va., May 25. Winchester May 25 (Cos. "A," "B," "C," "G" and "I"). Charlestown May 28. Defence of Harper's Ferry May 28-30 (Cos. "D," "F" "H" "K" and "L"). Near Harper's Ferry June 9. Expedition to Madison Court House, Culpeper And Orange Court Houses July 12-17. Near Culpeper July 12. Rapidan Station July 13. Madison Court House August 8. Battle of Cedar Creek August 9. Pope's Campaign in Northern Virginia August 16-September 2. Fords of the Rappahannock August 21-23. Fauquier, White Sulphur Springs, August 23-24. Gainesville August 28. Groveton August 29. Bull Run August 30. Chantilly September 1. Evacuation of Winchester September 2 (Cos. "H," "I"). Frederick, Md., September 6. Boonsboro, Md., September 7. Near Boonsboro September 10. Maryland Heights and Harper's Ferry September 12-13 (Cos. "H," "I"). Cut way through enemy's lines September 14 (Cos. "H" and "I"). Culpeper September 14. Sharpsburg September 15. Capture of Longstreet's trains (Cos. "H," and "I"). Rapidan Station September 16. Duty in the Defences of the Upper Potomac covering Washington, D. C., till December. Manassas, Va., October 23-24. Affair opposite Williamsport October 29 (Detachment). Reconnoissance from Bolivar Heights to Rippon, W. Va., November 9 (2 Cos.). Reconnoissance to Winchester December 2-6 (Detachment). Battle of Fredericksburg December 12-15. Dumfries December 27. Duty in the defences of the Upper Potomac till April, 1863; near Cumberland, Md., Grove Church, near Morrisville, January 26. Chancellorsville Campaign April 27-May 6. Stoneman's Raid April 27-May 8. South Anna Bridge, near Ashland, May 3. Brandy Station, or Fleetwood, and Beverly Ford, June 9. Aldie June 17. Frederick, Md., June 21 (Detachment). Upperville June 23. Middleburg June 25. Westminster June 30. Battle of Gettysburg, Pa., July 1-3. Emmettsburg July 4-6. Middletown July 5. Leitersburg July 7. Cavetown July 8. Hagerstown and Old Antietam Forge, near Leitersburg, July 10. Shepherdstown July 14 and 16. Beverly Ford September 6. Advance from the Rappahannock to the Rapidan September 13-17. Culpeper Court House September 13. Rapidan Station September 13 and 15-16. Raccoon Ford September 15. White's Ford September 21. Bristoe Campaign October 9-22. Germania Ford and James City October 10. Near Warrenton October 11. White Sulphur Springs October 12-13. Bristoe Station October 14. Near Centreville and Brentsville October 14. Advance to line of the Rappahannock November 7-8. Mine Run Campaign November 26-December 2. Grove Church, near Morrisville, November 26. Parker's Store November 29. Duty in Middle Department till June, 1864. Princeton May 6. Jeffersonville May 8. Wier Bottom Church, on Bermuda Hundred Front, Va., June 16-17. Richmond and Petersburg R. R. June 19. Deep Bottom July 21. New Market Heights July 27-28. Strawberry Plains, north of the James, August 14-18. Flusser's Mills August 14. Deep Run August 16-18. Siege of Petersburg August 25-September 27. Battle of Chaffin's Farm September 28-30. New Market Heights October 7. Darbytown Road October 13. Fair Oaks October 27-28. Smithfield December 7. Duty before Richmond to March, 1865. Scout to Long and Bottom's Bridge January 30, 1865. Expedition to Fearnsville and Smithfield February 11-15. Appomattox Campaign March 28-April 9. Dinwiddie Court House March 30-31. Five Forks April 1. Sutherland Station April 2. Burgess Mills April 3. Deep Creek April 4. Amelia Court House April 5. Sailor's Creek and Harper's Farm April 6. Farmville April 6-7. Appomattox Court House April 9. Surrender of Lee and his army. March to Danville April 23-29. Duty in the Department of Virginia till August. Mustered out August 8, 1865.

Regiment lost during service 3 Officers and 65 Enlisted men killed and mortally wounded and 3 Officers and 130 Enlisted men by disease. Total 201.