She bequeathed her large estate to establish trust funds for maintaining hospitals, educational facilities, community projects and cultural venues in and around Boston, Massachusetts and Westbrook, Maine.

[3] Warren's mother was the daughter of Dorus Clarke, a Congregationalist minister[4] and she, "a powerful and dominant personality",[5] was the parent who was most often present in the children's lives.

[10] Warren was part of a group of friends which included Emily Greene Balch, Katharine Coman, and Vida Scudder, all of whom had ties to Wellesley College.

[12] As was expected of women of her social class, Warren became involved in social betterment schemes, such as the Fatherless and Widow's Society, for which she served as trustee beginning in 1879;[13] the Boston Home for Incurables, of which she became a trustee in 1884;[14] as well as providing funds for educational facilities like the Bradford Academy in Haverhill, Massachusetts, the International Institute for Girls [es] in San Sebastián, Spain; Robert College in Constantinople; and the Tuskegee Institute of Alabama.

[18] Having written poetry since childhood, in 1892,[19] Warren published a novel, Miss Wilton, extolling the virtues of both Americanism and Christianity,[20][21] to mixed reviews.

[25] The settlement house worked to provide links to education and employment for women and men, and included access to a library, nursery, school, and a gymnasium, the latter of which was purchased by Warren.

[26] In 1896, though she had long opened the grounds of Cedar Hill for social events, Warren constructed a maze on the property of Arborvitae for the enjoyment of herself and neighbors.

She left a trust to provide for public facilities, recreation and education in Westbrook, Maine,[36] which became known as the Cornelia Warren Community Association.