Collection
- Night Photos Taken Before and After the Earthquake and Fire, 1901-19092
- Noah Scovell collection, 1789-180414
- Norwalk, Ohio family photograph albums, ca. 1920s2
- Notes about Children in Teachers' Institute Note Book, [ca. 1890s]2
- O. N. Bradbury papers, 1864-18747
- Oberlin, Ohio Photograph Album, ca. 1860s-1900s2
- Oliver Hazard Perry papers, 1796-1969 (majority within 1812-1819)33
- Olney Family Photograph Albums, ca. 1895-19102
- Olof Peter Ahlgren account book, 1855-1889 (majority within 1855-1881)2
- Ornithology studies, 18992
- Pageant of the Dunes Photograph Album, 1917-19182
- Painted Bulletin Advertising Association Book, 1923-19242
- Paul A. Meunier Photograph Albums, 1942-19492
- Pennsylvania Burial Removal permits, 1906-19092
- People Photographed While Reading Photograph Album, ca. 1870s-1900s2
- Peter A. Sickal diary, 1884-18862
- Peter Force papers, 1774-1868 (majority within 1820-1867)16
- Peter Warren papers, 1738-1751 (majority within 1744-1751)288
- Pilsbury-Heath family letters, 1828-18542
- Point Lookout Prison Camp collection, 1863-1865 (majority within 1863-1864)21