The Morgan Lewis Papers consists primarily of the land dealings and personal correspondence of Morgan Lewis (1754-1844) and his family members, including correspondence, accounts, leases, mortgages, wills, maps, surveys, rent rolls, commissions, printed materials, and notes. They cover his time as a solider in the American Revolution and the War of 1812, as a jurist, and as governor of New York and primarily describe the business and land dealings of Morgan Lewis and his extended family. The collection also contains the land dealings and correspondence of his son-in-law, Maturin Livingston, the land dealings of Henry Beekman, his wife's maternal grandfather, and the correspondence of his daughter, Margaret Lewis Livingston, and his wife, Gertrude Livingston Lewis.

Also included in the collection are an 1801 copy of Robert R. Livingston's will; a document from 1805 entitled "The Sins of the United States" and signed by "Shiloh" that was sent to "The Governor of the State of New York" when Morgan Lewis held that position; letters from 1806 relating to Maturin Livingston's removal as recorder of New York; a letter from DeWitt Clinton on November 15, 1824, favoring Andrew Jackson for president; letters from 1830, 1831, and 1842 pertaining to Masonic matters, including an 1842 letter from James Herring suggesting that Lewis contact John Jacob Astor to obtain funding for a new Masonic building; and Margaret Livingston's correspondence from the early 1840s regarding the antirent agitation, including a letter from P.P. Wright in August of 1845 describing the murder of Sheriff O.N. Steele in Delaware County, New York.

The majority of the collection is composed of land deals negotiated in Duchess and Delaware counties in New York between Morgan Lewis and various renters. Materials prior to 1775 deal primarily with the land dealings of Henry Beekman, who was Gertrude Livingston's maternal grandfather. The correspondence is also primarily focused on the business, financial, and legal transactions of Morgan Lewis and his extended family.