- Augustine G. Kappes papers, 1899-1909 (MC 59)
- Bartholomew F. Fair papers, 1906-1966 (MC 24)
- Catholic Club of Philadelphia records, 1871-1923 (MC 23)
- Catholic Interracial Council (Philadelphia) recordings, 1950-1974 (MC 68)
- Catholic Philopatrian Literary Institute records, 1870-1950 (MC 26)
- Catholic Standard and Times records, 1909-1941 (MC 27)
- Catholic University of America records, 1947-1955 (MC 35)
- David Lynch papers, 1830-1875 (MC 13)
- Edward F. Hawks papers, 1900-1952 (MC 15)
- Eleanor C. Donnelly papers. 1873-1905 (MC 48)
- Elizabeth Ann Seton letters, 1799-1818 (MC 44)
- Elizabeth Sarah Kite papers, 1865-1941 (MC 2)
- Francis B. Gallagher collection of Fenian Brotherhood records, 1862-1870 (MC 14)
- Herman Joseph Heuser papers, 1872-1933 (MC 1)
- Irish College, Rome. Transcripts, 1832-1848 (MC 53)
- James F. Connelly papers, 1790-1974 (MC 67)
- John Gilmary Shea Correspondence, 1836-1891 (MC 51)
- John J. Bonner papers, 1909-1945 (MC 49)
- John W. Keogh papers, 1906-1960 (MC 50)
- Joseph M. Corrigan papers, 1896-1942 (MC 25)
- Lawrence Francis Flick papers, 1889-1930 (MC 18)
- Marian Year collection, 1954 (MC 6)
- Mark Antony Frenaye papers, 1807-1868 (MC 16)
- Martin I. J. Griffin papers, 1842-1911 (MC 8)
- Martin, Campbell, and Furlong families papers, 1795-1963 (MC 90)
- Mary Brackett Willcox papers, 1807-1864 (MC 10)
- Patrick Coad family papers, 1798-1880 (MC 37)
- Patrick Reilly papers, 1828-1878 (MC 42)
- Robert M. O’Reilly papers, 1862-1925 (MC 34)
- Samuel Cooper papers, 1769-1945 (MC 56)
- Thomas Cooke Middleton papers, 1859-1917 (MC 7)
- Thomas Lloyd family papers, 1766-1867 (MC 45)
- Walter George Smith papers, 1836-1933 (MC 47)
- William C. White letters, 1861-1869 (MC 17)
- William J. Lallou papers, circa 1890-1973 (MC 55)