Hiram Burnham was born in Narraguagus (now Cherryfield), Maine. According to the modest stone in Pine Grove Cemetery there, he was "killed in battle . . . September 9, 1864, ae. 50 years," the only discoverable clue to the date of his birth. Prior to the outbreak of the Civil War, he is described by a collateral descendant as having been "a very active man in Cherryfield . . . County Commissioner and also coroner. He was a lumberman and a leader of men." Burnham was mustered into service on July 15, 1861, as colonel of the 6th Maine, a regiment he had helped recruit and which lost thirteen commissioned officers in action in less than twelve months. The 6th Maine took part in the Peninsular campaign as a part of Winfield S. Hancock's brigade of W. F. Smith's division of the IV Corps. Here Burnham began to gain the notice of his commanding officers, eventually winning the commission of brigadier general of volunteers to rank from April 26, 1864. At Antietam (Sharpsburg) the division was part of the VI Corps. At the battle of Fredericksburg in December, 1862, where the corps was not heavily engaged, Burnham was in brigade command for a time. In the celebrated campaign of Chancellorsville, the VI Corps, under John Sedgwick, was ordered to take the heights at Fredericksburg which had cost Ambrose E. Burnside heavy casualties five months previously. Here the 6th Maine had its major and four of its ten captains shot dead on a field which did not greatly distinguish either Sedgwick or his Confederate opposite, Jubal Early. Again mainly in reserve at Gettysburg, Burnham fought gallantly in the Overland campaign of the spring of 1864. He was promoted to brigadier general of volunteers to rank from April 26, 1864, and in the subsequent operations against Petersburg commanded a brigade of the XVIII Corps. While engaged in a probing operation to determine the degree of Confederate resistance at a position then known to the Confederates as Fort Harrison (on the outer line of the Richmond defenses, below Chaffin's Bluff) Burnham was killed on September 29, 1864.
Reference: Generals in Blue. Lives of the Union Commanders by Ezra J. Warner. Louisiana State University Press. Baton Rouge.