from the Frederick Daily News, July 26, 1916:
Seized with a heart attack while in the yard of his home on East Third street, Charles B. Mattoon, a well known Frederick resident and Civil War veteran, dropped dead yesterday evening. Mr. Mattoon had been in poor health for the past year and for a long time had been a sufferer of asthma. He was critically ill early in the spring but recovered to the extent that he was able to be about the house and garden. Yesterday he arose early and was in the best of spirits. Despite the heat, he took a walk about 6 o'clock to his garden and it was while there that the fatal heart attack came. Death resulted instantly. Mr. Mattoon was 76 years of age.
With the death of Mr. Mattoon, there survives but one of that famous regiment, known as the "First Connecticut Bulldogs". The Connecticut volunteers passed through the four years of the Civil War and at the end of that time the regiment returned with a total of 77 war hardened men.
The funeral of Mr. Mattoon will be held from his late home Sunday afternoon at 1.30 o'clock, with services being conducted by Rev. G.D. Kidner. Interment will be made in Mt. Olivet cemetery. F. Schroeder has charge of the funeral arrangements.
When but a mere youth and in response to the President's call to arms, Mattoon, then a resident of Canaan, Conn., enlisted. The men selected for the ranks of that regiment were perfect specimens of manhood. They represented the pick of the men of Connecticut and surrounding states.
The Fifth Regiment Connecticut Volunteers served its own State nearly three months and served the government of the United States four years, less two days, and during that whole period was never called upon for any duty but what it responded to was alacrity. In many fights and battles it never fought behind breastworks although it built miles upon miles of them. It fought always in the open field and was never, with one exception, Cedar Mountain, driven from the field that is occupied when the battle began.
Although he was wounded several times during his service in the war, he was never absent from his regiment being carried along in the hospital wagon. He took part in the march to the sea. The regiment covered a total of 589 miles.
Although he rarely talked of the part he took in the war, when in a reminiscent mood, Mr. Mattoon would tell interesting stories of the war, the food they were given to eat, the hardships, and the meager pleasures that come to a soldier while in war.
He is survived by the following children: William F. Mattoon, Baltimore; Charles A. Mattoon, Baltimore; Mrs. Bernard Landwheir, Baltimore; R. Lee Mattoon, Edward Mattoon, and Mrs. James Gilbert, Frederick. Two sisters and one brother also survive: Mrs. Charlotte Bristol, Mrs. Annie E. Stone, and John E. Mattoon, New York.

Charles Baldwin Mattoon funeral notice, Frederick Daily News (MD), 31 Jul 1916

Charles Baldwin Mattoon obituary, Frederick Daily News (MD), 29 Jul 1916