The following data is extracted from Biographies of Croydon, Sullivan County, New Hampshire.
SHERMAN COOPER, Son of Hon. Lemuel P. Cooper, was born Aug. 20, 1833. He received his academical education at Meriden, N. H., studied medicine in New York City, and graduated at the New York Medical College in 1856. The following year he was deputy resident physician of Blackwell's Island Hospital. He settled at Claremont in 1858. He entered the army in 1861, as Assistant Surgeon of the 6th Regt. N. H. Vols:, but was promoted to the rank of Surgeon in March, 1863. At the end of three years, in 1864, he returned to Claremont and resumed the practice of of his profession.
Source: Biographies of Croydon, Sullivan County, New Hampshire