Series II. Whittier Correspondence: Letters Received contains over 1,000 letters dating from 1829 to 1892. The series is also arranged chronologically and indexed alphabetically by name of correspondent. Included in this series are large quantities of letters from friends, colleagues in political and reform activities, relatives, as well as a portion of the vast amount of mail Whittier received from admirers. Letters from James Fields discuss the publication of Whittier's work. Letters from Abby and Phebe Woodman, Lizzie Whittier, and Whittier relatives Ada and Gustavus Cambett concern daily life of some of the people Whittier was closest to. Whittier had a large set of correspondents in literary circles, and the collection contains letters from James Russell Lowell, William Dean Howells, and Oliver Wendell Holmes. A large part of Whittier's audience was composed of women, and he was known for the help and advice he gave to women writers. Letters from Mary Abigail Dodge (Gail Hamilton), Lucy Larcom, Sarah Orne Jewett, Annie Fields, Celia Thaxter, and Elizabeth Stuart Phelps discuss a variety of literary and personal matters. Letters from abolitionist Henry I. Bowditch, Massachusetts Senator Charles Sumner, and Harriet Beecher Stowe reflect Whittier's activity in the anti-slavery movement. The letters of Whittier's distant relative Hannah Neall concern the continuing moral dilemma that the Quaker community felt over the Civil War. Whittier helped the former slave Charlotte Forten, and two letters written in 1863 discuss her career in the North.

Letters from strangers comprised the majority of mail that Whittier received as he grew older. Perhaps the best indication of his inundation is the fact that many of Whittier's poetry manuscripts are written on the backs of 'fan-mail' letters and autograph requests. Letters from Mumford, Underwood, and Duprez all discuss Southerners whose views have been swayed by Whittier's writings. Of the more typical letters, Rockwell's (February 28, 1873) discusses his appreciation of Whittier's writing. See Appendix I for an index to Whittier's correspondence.