Born Benjamin Butler Clapp to Julia Hyde Butler & James Clapp, he was adopted by his grandfather Dr. Benjamin Butler after his mother died in 1832, and took the name Benjamin Clapp Butler. He studied the law in Saratoga, NY and was owner and editor of the Saratoga Sentinel. He moved to Luzerne in Warren County, NY in 1845 and by 1855 and to at least 1860 he was a lawyer there.
He enrolled on 1 January 1862 at Albany, NY and was commissioned Lieutenant Colonel of the 93rd New York Infantry on 3 February.
 
On the Campaign
He was in command of the 93rd New York Infantry, part of the Headquarters Guard, Army of the Potomac.
 
The rest of the War
He was wounded in the hand in action on 2 October 1864 at Poplar Springs Church, VA and mustered out on 2 February 1865 at Petersburg, VA.
 
After the War
He returned to Luzerne, NY and lived there the rest of his life.
 
References & notes
His service data from the State of New York.1 Personal details from family genealogists, the New York State Census of 1855, the US Census of 1860, and a bio sketch [pdf] from Warren County. His gravesite is on Findagrave. His picture from a photograph in the collection of the New York Military Museum. Steve Manganiello pointed us to another nice copy online from the Library of the University of Washington.
He married Mary Ann Skinner (1820-1901) in June 1854 and they had a daughter Mary.