Letters between Pruyn and various individuals who were involved in an important case brought before the Supreme Court in 1864 to determine the rights of organizations to bridge navigable streams. Pruyn argued the case successfully for the Hudson River Bridge Company, for which he was counsel. The collection depicts Pruyn's activities on behalf of the company and includes his correspondence pertaining to the case with William Henry Seward, James Moore Wayne, and S.L. Fairchild.