Written from China to his family, the letters of James Bancker contain descriptions of the social life of the Americans and English in China, of Hong Kong after the British acquisition of that place, and of anti-British riots in Canton. A long letter describes the outward voyage from New York to Canton; several letters given an account of a visit to the Philippines; and there is a partial journal of Bancker's return home through the Red Sea.

In addition to family and business correspondence, the Charles Nicoll Bancker Family Papers contains various documents, such as a furniture inventory volume (30pp.); a Daybook, 1795-1800 (120pp.); and a very interesting journal (unidentified, but by one of the Banckers, and filed under "Description of a trip..."), from New York to Albany and back, between July 20-Aug. 15, 1793 (1 vol., 31 pp.). It contains detailed observations of the Hudson River and the towns along the way. Bancker was involved in business and trade prior to 1826, and in insurance after that date, so there is material relating to those topics in this collection. He owned a substantial library of the period, which was used by Charles Wilkes's Expedition after 1837 (see Reynell Coates to Bancker). This library, along with Bancker's notable scientific instrument collection, was sold after his death and there are published auction catalogues in the collection. There is much family correspondence from: Anne E. Bancker, Charles Gerard Bancker, Evert Bancker, Sarah U. Bancker, Violetta Bancker Talbot, Elizabeth Bancker Teackle, and John Teackle.