- Three-page letter marked 'Confidential' to Lysander Spooner of Boston [Massachusetts] requesting his participation in an Executive Committee formed to advocate for the enlistment of blacks to fight in the Civil War. Signed by George L. Stearns on behalf of the Committee. This letter is part of the Slavery collection in New-York Historical Society.
- Undated pledge of moneys to be paid to Lysander Spooner for "a review of Judge Kane's late decision, that the U.S. Courts have no constitutional right to punish for contempt without trial by jury." Signed by several prominent abolitionists, including Ellis Gray Loring, Francis Jackson, and Samuel E. Sewall.
- One-page letter dated December 28, 1850, from Stephen P. Andrews in New York City, to Lysander Spooner of Boston [Massachusetts], reporting on the distribution of books sent by Spooner to Freeman Hunt, [William Cullen] Bryant, [Horace] Greeley, and Park [Parke] Godwin. Includes mention of a "card" [possibly a petition] that Andrews suggests having signed in Boston and then sent to New York for additional singatures.