The Lewis Cass papers contain a letter Lydia H. Sigourney wrote to Lewis Cass, dated 17 December 1860.
The George Brinley papers contain 2 letters Lydia H. Sigourney wrote to George Brinley (d. 1857), dated 24 April 1843 and 25 December 1860.
The Huntington family scrapbook contains two letters that Lydia H. Sigourney wrote to the Hannah (Phelps) Huntington, a letter to Maria (Perit) Huntington, and a letter in dedication of the 1857 Huntington family reunion. These letters included poems that had not been published at the time.
Lydia H. Sigourney's autograph may be found in the Martha Leach Packard commonplace book and the Russell-McCabe autograph album.
The William L. Clements Library also holds a significant selection of Lydia H. Sigourney's publications.
Dexter, Franklin Bowditch. "George Griffin." In Biological Sketches of the Graduates of Yale College with Annals of the College History. Volume 5. New York: Henry Holt and Company, 1911: 286-287.
Remains of the Rev. Edmund D. Griffin, Compiled by Francis Griffin: A Biographical Memoir of the Deceased, by the Rev. John McVickar, D.D. 2 vols. New-York, 1831.
Walworth, Reuben Hyde. Hyde Genealogy: Or, the Descendants, in the Female as well as in the Male Lines, from William Hyde, of Norwich, with Their Places of Residence, and Dates of Birth, Marriages, &c., and Other Particulars of Them and Their Families and Ancestry. 2 vols. Albany, NY: J. Munsell, 1864.
Zagarell, Sandra. "Lydia Howard Huntley Sigourney." In The Heath Anthology of American Literature. 5th ed. Paul Lautner, ed. Online.