The Charles Williamson Incoming and Outgoing correspondence pertains almost exclusively to business matters, and primarily to Williamson's development and management of the central New York state land purchased by Pulteney Associates in 1791. Correspondents include John Johnstone, Patrick Colquhoun, Viscount Henry Dundas (Lord) Melville, Robert Morris, William Pulteney, Samuel Swartwout, and Charles Cameron. Family correspondence includes letters to and from Williamson's father Alex Williamson, and brothers David and John Williamson. Many letters are photostats and transcriptions compiled by researcher Isaac Joslin Cox and are noted as such.