This journal pertains to his travels in the eastern part of the United States.

These journeys of botanical exploration include information regarding plants, and his remarks on the condition of remote settlements he visited. The journals cover the territory from Hudson's Bay to the Indian River in Florida, and from the Bahama Islands to the banks of the Mississippi.

This correspondence is principally concerned with business between Pershouse and his brother James in England, with comments on conditions and events in the United States, including anti-British feeling, Thomas Paine's return to America, Jefferson's administration, and immigration. The papers include Pershouse's journal (1800-1838), which includes accounts of travels in England, France, and the United States, letterbooks (1836-1862) of Henry Pershouse, nephew of John, chiefly on business matters, and two volumes of Pershouse genealogical data, compiled by B.M. Pershouse Bayley (1899).