David McMurtrie Gregg (April 10, 1833 – August 7, 1916) was an American farmer, diplomat, and a Union cavalry general in the American Civil War. Early life and career Gregg was born in Huntingdon, Pennsylvania. He was the first cousin of future Pennsylvania Governor Andrew Curtin and the grandson of Pennsylvania Congressman Andrew Gregg. He graduated from the United States Military Academy (West Point) in 1855 and was given a commission as a brevet second lieutenant in the 2nd U.S. Dragoons Regiment (heavy cavalry). During his tenure at West Point, he interacted with two classmates who would become great cavalry generals—an opponent and a commander, respectively: J.E.B. Stuart, class of 1854, and Philip Sheridan, class of 1853. His first real assignment was in the New Mexico Territory, as a company commander in the 1st U.S. Dragoons. His unit was ordered to California and he traveled with his friend Dorsey Pender; they later bought a racehorse together. His company then marched to Fort Vancouver, in Washington Territory. During this tour of duty, Lt. Gregg had his first taste of combat, engaged with 160 men against 1,000 Indian warriors, who had surrounded them. The fighting lasted for three days, although casualties were minor, and Gregg managed a fighting retreat. Civil War At the start of the Civil War, Gregg returned to Washington, D.C., where he was promoted to captain in the 3rd U.S. Cavalry, followed soon by a transfer to the 6th U.S. Cavalry. He developed typhoid fever and barely escaped death when his Washington hospital caught fire. In January 1862 he became colonel of the 8th Pennsylvania Cavalry. Gregg and the 8th Pennsylvania fought in the Peninsula Campaign, where he distinguished himself in the Seven Days Battles, expertly screening retreating Union infantry. The Battle of Antietam was his next engagement, but cavalry played little role. He received a furlough and married Ellen F. Sheaff on October 6, 1862, in Montgomery County, Pennsylvania; the couple honeymooned in New York City. Gregg was promoted to brigadier general just before the Battle of Fredericksburg. As at Antietam, the cavalry was underutilized and held in reserve. He commanded a brigade in the division of Alfred Pleasonton. Gregg was sent to assume command of another cavalry brigade when its commander, Brig. Gen. George Dashiell Bayard, was killed by an artillery shell that reached behind the infantry lines. After Maj. Gen. Joseph Hooker assumed command of the