Lucy Cornelia Lynde Hartt was born on September 7, 1846, in Warsaw, Wyoming County, New York.

She was an educator, a woman of great culture and refinement, and with a strong sense of justice. In 1868, she married Charles Frederick Hartt (1840-1878), geologist, paleontologist, and naturalist. She became deeply interested in his scientific work and she accompanied him on a trip to Brazil in 1876. After her husband's death from yellow fever in 1878, Mrs. Hartt became interested in education. She taught at the Brooklyn Heights Seminary, in Mrs. Reed's school in New York City, and was a principal of a Staten Island school. Then she came to Buffalo where she served as principal of the Seminary for 13 years. She was also a president of its Graduates' Association. When she relinquished her duties, she went to Boston to spend the last years of her life with her son Rollin Lynde Hartt and daughter Mary Bronson Hartt, both writers for the Boston Transcript.

She died on February 16, 1912, in Boston, Massachusetts, and is buried in Buffalo, New York.