David McMurtrie Gregg was born on April 10, 1833, at Huntingdon, Pennsylvania. He was the third of nine children born to Matthew Duncan Gregg and Ellen McMurtrie. Trained as a lawyer, Matthew Gregg was part owner and ironmaster of the Potomac Furnace, an ironwork in Loudoun County, Virginia. David Gregg’s grandfather, Andrew Gregg was a United States Congressman from Pennsylvania who served in the House of Representatives from 1791 to 1807, and then in the Senate from 1807 to 1813.
David Gregg’s father died of fever on July 27, 1845, when young Gregg was just twelve years old. Gregg’s mother moved her children to live with family members in Hollidaysburg, Pennsylvania, where, tragically, she died just a year later on August 17, 1847. Gregg and his older brother, Andrew, went to live with their uncle, David McMurtrie III in Huntingdon, while Gregg’s siblings were scattered amongst relatives. The uncle ensured that both boys received proper educations.
David Gregg first attended the John A. Hall School in Huntingdon. In 1849, he enrolled at the Milnwood Academy, a preparatory school at nearby Shade Gap. The next year he followed in Andrew’s footsteps, attending the University of Lewisburg (later Bucknell University). In 1850, Representative Samuel Calvin of Blair County secured an appointment for Gregg at the United States Military Academy. Before he enrolled, however, tragedy visited Gregg’s life again when Andrew died on March 11, 1851.
U.S. Military Academy
Gregg entered West Point on July 1, 1851. While enrolled there he garnered a reputation as a fine horseman, which contributed to his eventual renown as a cavalry officer. One class ahead of Gregg was future Confederate cavalry commander J. E. B. Stuart, who Gregg would encounter many times during the Civil War. Gregg graduated on July 1, 1855, finishing eighth in his class of thirty-four cadets.
At the commencement ceremonies, Gregg met Ellen Frances Sheaff, the granddaughter of former Pennsylvania Governor Joseph Hiester. Eight years later, the couple wed in Philadelphia during the Civil War. Their marriage produced two sons, George Sheaff Gregg and David McMurtrie Gregg.
U.S. Army Officer
Upon graduation from the academy, Gregg received a brevet promotion as a second lieutenant and assignment to garrison duty with the 2nd U.S. Dragoons at Jefferson Barracks, Missouri. On September 4, 1855, army officials promoted Gregg to second lieutenant with the 1st U.S. Dragoons and sent him to Fort Union, New Mexico. The army transferred Gregg to California in 1856 and then to the Washington Territory in 1857. In Washington, Gregg campaigned against American Indians until 1861. On March 21, 1861, army officials promoted Gregg to first lieutenant and ordered him to return to California. Soon after the Civil War began, the army promoted Gregg to the rank of captain with the 6th U.S. Cavalry on May 14, 1861, and ordered him east to the defenses of Washington, DC.
On the recommendation of his first cousin, Governor Andrew Gregg Curtin of Pennsylvania, Gregg received an appointment as colonel of the 8th Pennsylvania Cavalry in the volunteer army on January 24, 1862. During George B. McClellan‘s Peninsula Campaign (March 17–August 14, 1862), Gregg also commanded the Cavalry Brigade of the 4th Corps of the Army of the Potomac. Later in the year, Gregg led federal troops during the Maryland Campaign (September 4-September 20, 1862).
Following his wedding on October 6, 1862, and a brief honeymoon, Gregg returned to active duty. The War Department promoted him to brigadier general of volunteers on November 29, 1862, prior to his participation in the Battle of Fredericksburg (December 11-15, 1862). During that battle, Gregg assumed command of the 2nd Brigade of the Army of the Potomac’s Cavalry Division following the death of Brigadier General George D. Bayard.
After the federal defeat at Fredericksburg, Major General Joseph Hooker replaced Major General Ambrose Burnside as commander of the Army of the Potomac. On February 5, 1863, Hooker reorganized the army, centralizing his horsemen and creating a cavalry corps comprising three divisions commanded by Major General George Stoneman. Hooker placed Gregg in charge of the 3rd Division of the newly created Cavalry Corps of the Army of the Potomac in December 1862.
When Hooker began his 1863 spring offensive, which would culminate at the Battle of Chancellorsville (April 30-May 6), he sent most of Stoneman’s cavalry on a major raid behind enemy lines near Fredericksburg. Stoneman’s Raid of 1863 began on April 13 when the cavalry commander led 10,000 federal troopers out of the main camp of the Army of the Potomac near Falmouth, Virginia, with orders to sever the Army of Northern Virginia’s supply lines, forcing them to abandon their defenses at Fredericksburg.
Two days later, torrential rains began falling, making the Rappahannock River impassable and placing Hooker’s plan far behind schedule. Once across the river, Stoneman’s men destroyed some railroad lines between Richmond and Fredericksburg, but could not completely sever the Rebel supply lines. Losing contact with Hooker on April 30, Stoneman did not rejoin the army until May 7, depriving Hooker of his cavalry at the Battle of Chancellorsville.
Eager to find a scapegoat for the federal defeat at Chancellorsville, and deflect criticism from himself, Hooker placed much of the blame on Stoneman. On June 7, 1863, Hooker sacked Stoneman and placed Brigadier General Alfred Pleasonton in charge of the Cavalry Corps. Hooker transferred Gregg to the command of the 2nd Division.
After the Rebel victory at the Battle of Chancellorsville, Robert E. Lee took the war to the North. As Lee marched the Army of Northern Virginia north through the Shenandoah Valley on the western side of the Blue Ridge Mountains, he ordered Major General J. E. B. Stuart’s cavalry to screen his movements by riding in the same direction through the Loudoun Valley on the east side of the mountains.
Hooker and Pleasonton responded by forcing a series of cavalry engagements during June 1863, attempting to determine Lee’s intentions. On June 9, Gregg commanded the Left Wing of the Union cavalry at the Battle of Brandy Station, the largest cavalry engagement of the Civil War. Gregg’s troopers also engaged Stuart’s cavalry at the Battle of Aldie (June 17), the Battle of Middleburg (June 17), and the Battle of Hanover (June 21).
On the third day of the Battle of Gettysburg (July 3, 1863) Gregg, commanding three cavalry brigades, thwarted Stuart’s attempt to flank and assault the Union rear as they withstood Pickett’s Charge at Cemetery Ridge. Following the federal victory at Gettysburg, Gregg’s troopers harassed Lee’s army as it retreated to Virginia. Gregg spent the rest of 1863 operating against Confederate cavalry in Central Virginia, seeing action at Rapidan Station (September 14), Beverly Ford (October 12), Auburn (October 14), and New Hope Church (November 27).
Bypassed for Promotion
On March 7, 1864, President Abraham Lincoln appointed Ulysses S. Grant as General-in-Chief of the Armies of the United States. Grant sent Pleasonton to the Western Theater, replacing him with one of his personal favorites, Major General Philip Sheridan. As a senior division commander, Grant’s decision to bypass Gregg for promotion undoubtedly shocked and disappointed him, especially because Sheridan had very little cavalry experience. Gregg served as interim commander of the Cavalry Corps from the time of Pleasonton’s departure on March 26, 1864, until Sheridan assumed command on April 4, 1864. Upon Sheridan’s arrival, Gregg resumed his previous command of the 2nd Division.
During Grant’s Overland Campaign, Gregg took part in numerous skirmishes and several major engagements during the summer of 1864, including the Battle of Haw’s Shop (May 28, 1864), the Battle of Trevilian Station (June 11–June 12, 1864) and the Battle of Saint Mary’s Church (June 24, 1864).
Shenandoah Valley Campaign of 1864
In June 1864, Confederate General Jubal Early launched a major offensive into the Shenandoah Valley and parts of Maryland. By July, he was within view of Washington, DC. Although forced to retreat to the Valley after the Battle of Monocacy (July 9, 1864), Early’s force remained a threat to the nation’s capital. In early August, Grant placed Sheridan in command of the newly created Army of the Shenandoah and dispatched him (along with two divisions of the Army of the Potomac’s Cavalry Corps) to the Shenandoah Valley to deal with Early.
On August 1, 1864, the War Department brevetted Gregg to the rank of major general, making him eligible to command a corps. Grant then appointed him to command the rest of the Army of the Potomac’s Cavalry Corps during Sheridan’s absence.
Sheridan neared completion of his assignment in the Shenandoah Valley with his rout of Early’s forces at the Battle of Opequon (September 19, 1864), the Battle of Fisher’s Hill (September 21–22, 1864), and the Battle of Cedar Creek (October 19, 1864). With Early’s forces driven from the valley, Sheridan spent the next few weeks laying waste to farms, mills, and any other infrastructure that might provide sustenance or aid to the Confederate cause.
When Gregg learned Sheridan would resume his position as corps commander after returning from the valley, he resigned his commission from the army on February 3, 1865. Although Gregg’s resignation letter cited only “pressing private duties and business” at home that demanded personal attention, Gregg was unwilling to have Sheridan supersede him a second time.
During retirement, Gregg returned to Pennsylvania and later tried farming in Delaware. Quickly tiring of civilian life, he tried unsuccessfully to return to the service in 1868. On February 3, 1874, President Grant appointed Gregg as the United States Consul at Prague, Bohemia, but Mrs. Gregg grew homesick, so Gregg resigned on June 28, 1874. Upon returning to the United States in August, Gregg took up residence in Reading, Pennsylvania, where he became active in civic affairs. In 1891, Pennsylvania voters elected Gregg to one term as the state’s auditor general. In 1899, he declined a nomination for the office of state treasurer because of his declining health.
Gregg died on August 7, 1916, less than a year after his wife’s passing. He was buried at Charles Evans Cemetery in Reading.