| SURNAME | GIVEN NAME | YEAR | VOL. | PAGE | MISCELLANEOUS |
| OBENDOEFER | August | 1904 | 10 | 209 | MSD |
| OBENDOEFER | Leonard | 1904 | 10 | 210 | MSD |
| OBER | Martin | 1844 | 1 | ||
| OBER | Martin | 1844 | 1 | ||
| OBETZ | Christian | 1843 | 1 | ||
| O'BRIAN | Barnard | 1848 | 1 | ||
| O'BRIAN | Michael | 1 | |||
| O'BRIAN | Michael | 1856 | 1 | ||
| O'BRIEN | Michael | 1 | |||
| O'BRIEN | Thomas | 1892 | 2 | ||
| OBROCK | Walter Henry | 1937 | 20 | 99 | |
| O'BYRNE | John | 1872 | 1 | ||
| OCHABO | Joseph | 1925 | 12 | 20 | |
| OCHS | Henry | 1859 | 1 | ||
| O'CINNEY | Patrick | 1847 | 1 | ||
| ODENWELLER | Jacob C | 1887 | 2 | ||
| ODERICK | Theodore | 1 | |||
| O'DOGHERTY | Daniel | 1 | |||
| O'DONNEL | Arthur | 1806 | 1 | ||
| O'DONNEL | Charles | 1834 | 1 | ||
| O'DONNEL | Connel | 1806 | 1 | ||
| O'DONNEL | Connel, Jr | 1806 | 1 | ||
| O'DONNEL | Hugh | 1 | |||
| O'DONNEL | John | 1 | |||
| O'DONNELL | Arthur | 1806 | 1 | ||
| O'DONNELL | Connel | 1806 | 1 | ||
| OEHSTREICHER | Christian | 1813 | 1 | ||
| OERKEL | Henry | 1 | |||
| OESTERLING | John | 1836 | 1 | ||
| OESTERLING | Leonhard | 1836 | 1 | ||
| OFFSTEIN | Jacob C | 1928 | 16 | 18 | |
| O'FRAIL | Michael | 1863 | 1 | ||
| O'HARRA | john | 1 | |||
| OHE | Adam | 1844 | 1 | ||
| OHT | Valentine | 1855 | 1 | ||
| OLAJOS | Charles | 13 | 66 | ||
| OLCZAK | Joseph | 1918 | 5 | 4 | |
| OLDHAM | William R | 1889 | 2 | ||
| OLEN | Nick | 1925 | 13 | 8 | |
| OLEN | Jeffery David | 1963 | 29 | 19 | |
| OLENIC | John | 1942 | 25 | 30 | |
| OLEVER | John | 1 | |||
| OLEXA | John | 1944 | 26 | 90 | |
| OLEXSAK | John | 1940 | 22 | 112 | |
| OLINY | Anna | 1940 | 22 | 83 | |
| OLIRY | Alix | 1928 | 6 | 50 | |
| OLIVA | Savno | 10 | 145 | MSD | |
| OLKUS | Joseph | 1858 | 1 | ||
| OLKUS | Mathias | 1 | |||
| OLRICH | Lorenz | 1858 | 1 | ||
| OLSON | Mathilde | 1951 | 27 | 96 | |
| OLSSON | Charles A | 1890 | 2 | ||
| OLSSON | John | 1876 | 2 | ||
| OLSZANITSKI | Peter | 1939 | 22 | 7 | |
| OLUSZHAK | John | 1928 | 17 | 14 | |
| OLUSZHAK | Polly | 1941 | 24 | 152 | |
| OMARA | Patrick | 1876 | 2 | ||
| OMARA | Vangel Thomas | 1958 | 28 | 111 | |
| O'NEAL | Francis | 1 | |||
| O'NEAL | John | 1 | |||
| O'NEILE | Patrick | 1839 | 1 | ||
| ONUFER | Thomas | 1942 | 25 | 52 | |
| ONUFRAK | Frank | 1925 | 13 | 73 | |
| ONUFRAK | Nick | 1926 | 13 | 97 | |
| ONUFRAK | Annie | 1942 | 25 | 120 | |
| ONUFRAK | Anna | 1943 | 25 | 188 | |
| ORAVEZ | John | 1909 | 2A | 50 | |
| ORDASHEVSKY | Zinovy | 1939 | 22 | 2 | |
| ORDOS | Joseph | 1922 | 10 | 38 | |
| ORDOS | Julia | 1942 | 1A | 23 | Repartriated |
| ORDOZ | Elmer | 1925 | 13 | 72 | Name Changed to E. ERDIE 1942 |
| ORDY | Steve | 1923 | 9 | 92 | |
| ORENCHUCK | Katy, Mrs. | 1924 | 12 | 36 | |
| ORESCANIN | Mihailo | 1945 | 27 | 19 | |
| ORGOVAN | Balint | 1932 | 19 | 20 | |
| ORLANDO | Frank | 1940 | 23 | 45 | |
| ORLOWSKI | John | 1923 | 11 | 81 | |
| ORLOWSKI | Stella | 1944 | 26 | 66 | |
| O'ROKE | James | 1878 | 2 | ||
| OROWITZ | Ludwig | 1915 | 3 | 228 | |
| ORR | Charles | 1882 | 2 | ||
| ORR | James W | 1875 | 2 | ||
| ORR | John | 1875 | 2 | ||
| ORR | Samuel | 1838 | 1 | ||
| OSBORNE | John C | 1893 | 2 | ||
| OSCHA | Nicholas | 1878 | 2 | ||
| OSEE | Jacob C | 1855 | 1 | ||
| O'SHEA | Francis, Joseph, Rev. | 1870 | 1 | ||
| OSIPUK | Paul | 1940 | 23 | 86 | |
| OSIPUK | Anna | 1942 | 25 | 48 | |
| OSMER | Stephen | 1848 | 1 | ||
| OSMER | Dorothy Ann | 1945 | 27 | 30 | |
| OSMOND | Lily | 1940 | 22 | 93 | |
| OSTERMAN | Peter | 1920 | 4 | 80 | |
| OSTLAND | John | 1880 | 2 | ||
| OSTWINCH | Michael John | 1943 | 25 | 79 | |
| OSWATT | Charles, Joseph | 1840 | 1 | ||
| OTREMSKY | Luke | 1937 | 20 | 85 | |
| OTREMSKY | John | 1939 | 22 | 27 | |
| OTREMSKY | Mary | 1941 | 24 | 105 | |
| OTT | Falden | 1840 | 1 | ||
| OTT | Martin | 1840 | 1 | ||
| OTT | Vandel | 1840 | 1 | ||
| OTTE | Charles | 1 | |||
| OTTERSON | Oscar | 1910 | 2B | 30 | |
| OTTO | Peter | 1844 | 1 | ||
| OTTOLINI | Raffaele | 1917 | 5 | 20 | |
| OVERLITNER | Andrew | 1878 | 2 | ||
| OWENS | Lewis | 1880 | 2 | ||
| OWENS | Lillian | 1954 | 28 | 14 | |
| OWESSEN | Henrik, Carl, Andres | 1914 | 3 | 197 | |
| OYER | Finn P | 1925 | 13 | 79 | |
| OZANICK | Mate | 1922 | 8 | 38 | |
| OZECHOWSKI | Anthony | 1926 | 14 | 27 | |
| OZECHOWSKI | Jennie | 1938 | 21 | 93 | |