She married, in 1821, Thomas C. Doremus, a merchant, whose wealth thenceforth was freely expended in her benevolent enterprises.

Seven years later she became interested in the mission at Grand Ligne, Canada, conducted by Henriette Feller of Switzerland, and in 1860, was made president of the organization.

[1] Doremus aided in founding, in 1850, the House and School of Industry for Poor Women, becoming its president in 1867, and in 1854, became vice-president of the Nursery and Child's Hospital.

In 1855, she assisted J. Marion Sims in his project of establishing the New York Woman's Hospital, of which she was ultimately president.

During the American Civil War, she cooperated with the work carried on in the hospitals, ministering alike to the wounded from north and south.