Benjamin Henry Grierson (July 8, 1826 – August 31, 1911) was a music teacher, then a career officer in the United States Army. He was a cavalry general in the volunteer Union Army during the Civil War and later led troops in the American Old West. He is most noted for Grierson's Raid, an 1863 expedition through Confederate-held territory that severed enemy communication lines between Vicksburg, Mississippi and Confederate commanders in the Eastern Theater. After the war he organized and led the Buffalo Soldiers of the 10th Cavalry Regiment from 1866 to 1890.
Grierson was born in the borough of Allegheny, Pennsylvania, today a section of Pittsburgh. He was the youngest of five siblings. Grierson became afraid of horses when, at age eight, he was kicked and nearly killed by a horse, after which he hated horses. He eventually became a great cavalry commander.
In 1851, he became a music teacher and band leader in Jacksonville, Illinois. He married Alice Kirk of Youngstown, Ohio on September 24, 1854. The couple had seven children, four of whom survived to adulthood.
With the outbreak of the Civil War, Grierson enlisted as a volunteer aide-de-camp to Maj. Gen. Benjamin M. Prentiss. Promoted to major on October 24, 1861, he joined the 6th Illinois Cavalry and was promoted to colonel of that regiment on April 13, 1862. His regiment was engaged in a number of small skirmishes and raids on railroads and facilities in Tennessee and Mississippi that spring and summer. In November, he became a brigade commander in the Cavalry Division of the Army of the Tennessee. In December, he participated in the pursuit of Confederate Earl Van Dorn after his Holly Springs raid against the supply lines of General Ulysses S. Grant.
In the spring of 1863, he led Grierson's Raid, a major diversionary thrust deep into the Confederacy, ordered by Grant as part of his Vicksburg Campaign. Grierson departed from LaGrange, Tennessee, on April 17, in command of 1,700 men of the 6th and 7th Illinois and the 2nd Iowa Cavalry regiments. Over 17 days, his command marched 800 miles, repeatedly engaged the Confederates, disabled two railroads, captured many prisoners and horses, and destroyed vast amounts of property, finally ending in Baton Rouge on May 2. Historian John D. Winters in The Civil War in Louisiana (1963) reports that Grierson's raid "struck fear in the hearts of the citizens and somewhat demoralized the Confederate forces who failed to stop the move."
More importantly, Grierson diverted the attention of the Confederate defenders of Vicksburg away from General Grant's main thrust. Gen. Sherman considered Grierson's raid "the most brilliant expedition of the war." Grierson was promoted to brigadier general of volunteers in June. While ending his raid in Louisiana he was able to take part in Nathaniel P. Banks' siege of Port Hudson as commander of the XIX Corps cavalry.
In June 1864 Grierson returned to command a cavalry division in the Army of the Tennessee during William T. Sherman's Meridian Campaign. He was still in division command during Samuel D. Sturgis' ill-fated encounter with Nathan B. Forrest at the Battle of Brice's Crossroads. Shortly after that battle Grierson was transferred to command the Cavalry in the District of West Tennessee. He was attached to Andrew J. Smith's XVI Corps and fared much better against Forrest at the Battle of Tupelo.