Andrew Cornwall was born on January 25, 1822, in Portland, Connecticut, to Amos and Sybil Cornwall. His father was a farmer who owned $4,000 of real estate and $1,000 of personal property by 1860. He attended school in Portland until he was thirteen, when he reportedly “found employment at East Hampton, and became a hard and incessant worker.”
He married Elizabeth Whitmore on January 20, 1843, and they had at least three children: Henry, born on November 16, 1843; Dwight, born on July 14, 1851; and Demas, born on April 15, 1855. The family returned to Portland, and Cornwall worked as a farmer there. By 1860, he owned $6,000 of real estate and $2,000 of personal property. A decade later, he owned $7,000 of real estate and $4,500 of personal property. According to one writer, he was “thorough farmer, and became quite wealthy.”
Cornwall supported the Republican Party, and he served as a town selectman. He served in the General Assembly from 1884 to 1885. He died in Portland on July 7, 1894. As a local writer explained, he “was killed…by a steer which he was leading out of the pasture into his barn, when the animal turned quickly, knocking Mr. Cornwall down and trampling on him.” A later report, however, countered that he “died in reality of heart disease brought on by overexertion and excitement in trying to manage the animals.”