The Hallowell family papers, 1856-1891, consists of letters written to William Hallowell, his wife Mary (Post) Hallowell, and Mary's aunt Sarah (Kirby) Hallowell Willis. The letters mainly discuss personal affairs; many are letters of condolence after the death of William Hallowell in 1882.

The collection consists of letters written by and to Isabella Beecher Hooker (1822-1907) and her husband John Hooker (1816-1901). Included are almost daily reports from Isabella Beecher Hooker to her husband written from Washington, DC where, on January 12, 1872, she and Susan B. Anthony testified on behalf of a federal woman suffrage amendment before a hearing of the Senate Judiciary Committee.