The bulk of the collection deals with the younger Symmes and his work to promote his “concentric spheres” theory. Correspondence with editors, congressmen, military officers, diplomats and academic societies throughout the world attest to his efforts to arouse interest in his theory and to gain support for a scientific polar expedition. Personal correspondence with his brothers Daniel and Peyton, his wife Marianne, his mother Mercy, and other family members discuss life in Cincinnati, Ohio, and on frontier military posts in both war and peace, particularly Bellefontaine on the Missouri River, and early development of his theory. Major correspondents include prominent political and academic figures of the time.
The elder Symmes's papers deal with his business and land development, especially with Jonathan Dayton. Major topics discussed were the Miami Purchase and its early settlements, the government of the Northwest Territory, and military operations against the Indians. Biographical and genealogical information was extracted and summarized by Draper from the elder Symmes's correspondence and daybook.
