William Dwight was born July 14, 1831, in Springfield, Massachusetts, a descendant of John Dwight who settled in Dedham in 1635. After attendance at a private military school, Dwight entered West Point in 1849. That he "resigned in 1853 before graduation" is generally reported in accounts of his life; however, he "was discharged ... 31 January 1853 for deficiency in studies." He then engaged in manufacturing in Boston and Philadelphia until the beginning of the Civil War. In June, 1861, Dwight was commissioned lieutenant colonel of the 70th New York, a regiment whose colonel was Daniel Sickles. At the battle of Williamsburg on the Virginia Peninsula, Dwight's regiment suffered 50 per cent casualties and he was wounded, left for dead on the field, and taken prisoner by the Confederates. Soon exchanged and promoted to brigadier general to rank from November 29, 1862, Dwight commanded a brigade in Cuvier Grover's division of N. P. Banks's forces in Louisiana and was a leading participant in the reduction and surrender of Port Hudson. He acted as chief of staff to Banks during the celebrated Red River campaign and in this connection it was rumored that Dwight's principal interest was flushing out stores of Confederate cotton for shipment to Massachusetts mills. In July, 1864, he was transferred to command a division of Emory's XIX Corps and in the Shenandoah Valley campaign fought at Winchester, Fisher's Hill, and Cedar Creek. For alleged defamatory statements relating to other commands at Winchester and because of the allegation that Dwight had retired to a place out of gunfire to take his lunch during the battle, he was subsequently put in arrest. The charges seem to have died of inertia, and no action was taken; however, it is worth noting that Dwight's name was not included in the omnibus brevet promotions at the end of the war. Honorably mustered out on January 15, 1866, he had already moved to Cincinnati, where he became associated with his brothers in railroad management. He died in Boston on April 21, 1888, and was buried in Forest Hills Cemetery.
Reference: Generals in Blue. Lives of the Union Commanders by Ezra J. Warner. Louisiana State University Press. Baton Rouge.