Collection
- Paul G. Kauper papers, 1925-19741
- Paul Shapiro photograph collection, circa 1980-19831
- Penrod/Hiawatha Company postcard collection, 1950s-20171
- Perry Bullard papers, 1969-19921
- Peter Pollack papers, 1965-2009 (majority within 1980-2005)1
- Pittsfield Township records, 1830-19801
- Pond Family Papers, 1841-19391
- Postcard Collection, 1890s-[ongoing]1
- Religious Communities of Michigan Web Archive, 2010-20141
- Rice Aner Beal papers, 1843-18831
- Richard D. Ahern Papers, 1956-2004 (majority within 1956-1980)1
- Richard D. T. Hollister Papers, 1887-19601
- Richard G. Wilson papers, 1967-19691
- Richard Nims papers, 1880s-1990s (majority within 1937-1954)1
- Rinsey family papers, 1856-1950 (majority within 1913-1928)1
- Robert J. Harris papers, circa 1959-1963 and 1969-19731
- Robert P. Weeks papers, 1961-19701
- Roscoe O. Bonisteel Papers, 1903-19721
- Royal Arch Masons, Washtenaw Chapter No. 6 records, 1849-19721
- Royal S. Copeland Papers, 1892-19381