The Archives of The Morgan Library & Museum houses personal papers of Pierpont Morgan (1837–1913) and his immediate family, early records of the Morgan financial firms, and the records of the Morgan. Comprising correspondence, photographs and albums, documents, scrapbooks, and printed materials, the Archives is an important scholarly resource for the history of the Gilded Age, American economic development, and art collecting and connoisseurship.

A heavily used scholarly resource in the Archives is Morgan Collections Correspondence, which contains nearly eight thousand letters and invoices that document in great detail purchases of works of art, furniture, decorative items, and books and manuscripts made by Morgan from 1887 until his death in 1913. These papers provide essential provenance documentation for tens of thousands of works acquired by Morgan.

Family materials include substantial collections of papers of Pierpont Morgan, his son, J. P. Morgan, Jr., and his daughters Louisa Satterlee and Anne Morgan. The papers of the Rev. John Pierpont, maternal grandfather of Pierpont Morgan, include important resources for the study of nineteenth-century Unitarianism and reform movements, such as temperance, spiritualism, and abolitionism.

Although the Morgan does not hold the complete records of the Morgan financial firms, the Archives does include an important series of record books that document the syndicates formed by Morgan and his firms from 1882 to 1933, covering such key economic developments as the late-nineteenth-century reorganization of the American railroad industry and the 1902 creation of U.S. Steel, at the time the largest corporation ever formed.