The Daniel O'Sullivan collection consists of business records and correspondence related to Daniel Sullivan and his son Michael R. Sullivan who owned and operated a rooming house, and wholesale grocery and liquor store in the 1850s-1940s. Items also include a letter from Jeremiah O'Brien who fought for the 26th Regiment of the New York Volunteer Infantry and writes concerning battles fought during 1861-1862.

Folder consists of receipts from St. Mary's Catholic Church for pew rental, the Adams Express Company for shipments, Georg Wilhelm Gail for cigars, H. and H. W. Catherwood for whiskey, Smoot, Uhler and Co. for lumber, and Blacklock, Marshall and Co. for groceries, among others. There are also several hand-written receipts, all dating from 1837-1861.