(1825 - 1911)
Home State: New York
Command Billet: Commanding Regiment
Branch of Service: Infantry
Unit: 80th New York Infantry (20th Militia)
see his Battle Report
He had been a staff officer of the 20th New York State Militia since at least 1851 and was promoted to Major of the regiment in May 1855. At the start of the war, by then a 36 year old lawyer in Ulster County, he and the 20th were called up in April 1861 for three months' service. They were on railroad guard and picket duty Annapolis Junction, MD to the end of June. While there, on 2 June, Gates was elected Lieutenant Colonel of the Regiment after the resignation of the incumbent. At the end of June they marched to Baltimore and were in camp there to 30 July, when they returned to New York and mustered out.
In August 1861 he helped reorganize the regiment and recruit for another term of active service, and on 5 September he enrolled with the 20th Militia for 3 years of Federal Service in Kingston, and mustered as Lieutenant Colonel on 10 September. They were re-numbered the 80th New York Infantry on 7 December 1861.
On the Campaign
He commanded the regiment in Maryland as senior officer present; leading them in action at Turner's Gap on South Mountain on 14 September 1862 and at Antietam on the 17th.
The rest of the War
He was promoted to Colonel on 27 September 1862 (to rank from 11 September) after Colonel G.W. Pratt died of the wounds he received at 2nd Bull Run in August. He and his regiment had service in the Provost Guard of the Army of the Potomac and saw action again at Gettysburg, PA, noted particularly for their defense against "Pickett's Charge" on 3 July 1863. He mustered out on 22 November 1864 at the end of his term and was honored by brevet to Brigadier General of Volunteers (dated March 1865).
After the War
By June 1865 and to at least 1875 he was again practicing law in Kingston, Ulster County, NY, but by 1879 he was in Brooklyn, NY. He continued in State military service also, having been appointed Major General, New York National Guard in February 1867.
References & notes
His service from the Roster,1 his own History,2 and the New. York Adjutant General's Report of 1867. Personal details from family genealogists, the US Census for 1860-1880, and the NY State Census of 1855-1875. His gravesite is on Findagrave. His picture from a photograph in the Seward R. Osborne Collection.
He married Maria Van Leuven Overbach (1825-1889) in 1851 and they had 3 children.
His Civil War Diaries were edited by Mr. Osborne and published by Longstreet House in 1992.
More on the Web
There's a fine full-length standing photograph of him in uniform at the Library of Congress.
He published a history of the war - The War of the Rebellion - in 1884; it's online thanks to McMaster University.
12/16/1825; Oneonta, NY
07/05/1911; Brooklyn, NY; burial in Wiltwyck Cemetery, Kingston, NY
1 State of New York, Adjutant-General, Annual Report of the Adjutant General of the State of New York [year]: Registers of the [units], 43 Volumes, Albany: James B. Lyon, State Printer, 1893-1905, For the Year 1901, Ser. No. 29, pg. 1172 [AotW citation 26136]
2 Gates, Theodore Burr, The "Ulster Guard" (20th N. Y. State Militia) and the War of the Rebellion, New York City: Benjamin H. Tyrell, Printer, 1879 [AotW citation 26137]