These papers are principally personal correspondence of a father and son who were prominent Pennsylvania-German citizens, each of whom represented his district in Congress. Correspondents of the elder Muhlenberg include William Bigler, Simon Cameron, William J. Duane, John Meredith Read, and Richard Rush, and concern Democratic politics and Lutheran church business. Correspondents of the younger Muhlenberg include Benjamin H. Brewster, George M. Dallas, John K. Kane, Robert M. Patterson, and Seth Salisbury. There is also a group of letters to and from Muhlenberg relating to his biography of General Peter Muhlenberg, and a volume of commissions.