| | O'Connell | Jesse D. (US Army WWI) | 1886-09-28 | 1930-12-05 | 1930-12-03 | NEW-63,45,1 | Augustine |
| | Odiorne | Dolph Pearl Jr. (Vet, WWII) | 1923-09-01 | 0000-00-00 | 1944-05-01 | NEW-58,32,8A | |
| | Odiorne | Dolph Pearl Sr. (Vet) | 1886-00-00 | 1964-06-08 | 1964-06-05 | NEW-58,32,7 | Bowerman |
| | Ogden | Earl D. (Veteran) | 1932-05-19 | 2013-05-15 | 2013-05-11 | NEW-64,84,1 | Halbritter |
| | O'Gorman | Thomas (Vet) | 1890-00-00 | 1941-06-05 | 1941-06-03 | GM-C,156,1 | Pifer |
| | Okerbloom | Donald (Vet, US Army, Korea) | 1930-01-19 | 2002-12-27 | 2002-12-26 | GM-VET,193 | Pifer-Smith |
| | Okerbloom | Gary Eugene (Vet, US Marines, Vietnam) | 1948-02-11 | 1992-05-22 | 1992-05-20 | GM-VET,134 | Smith |
| | Okonski | William, Sr. (Vet, US Army WWII) | 1925-10-19 | 1997-04-30 | 1997-04-27 | NEW-54,21,1 | Halbritter |
| | Oleson | Robert Nichols (Veteran) | 1920-11-11 | 1972-12-08 | 1972-12-03 | GM-G,87,4 | Pifer |
| | Olson | Robert W. (Vet, US Navy, WWII) | 1923-03-17 | 1974-07-24 | 1974-07-21 | GM-VET,107 | Halbritter |
| | Olson | Willmar Edgar (Vet) | 1921-07-08 | 1959-12-22 | 1959-12-19 | GM-G,13,1 | Pifer |
| | Onderdonk | Howard C. (Vet, US Army, WWII Korea) | 1928-04-15 | 2010-10-20 | 2010-10-16 | GM-K,32,1 | Halbritter |
| | Opfer | Paul Gordon (Vet, US Navy, Vietnam) | 1953-09-28 | 2001-09-17 | 2001-08-22 | GM-VET85,2 | Halbritter |
| | Orias | John P. (Vet, US Navy, WWII) | 1923-01-23 | 1985-11-25 | 1985-11-22 | GM-VET,178 | Halbritter |
| | Orr | Arthur (Vet, US Army, WWI) | 1894-05-03 | 1975-02-03 | 1975-01-31 | GM-U,26,2 | |
| | Orr | James W. Dr. (Vet) | 1821-00-00 | 1888-09-08 | 1888-09-06 | CITY-63,1,4 | |
| | Ortmann | William Henry (US Army) | 1927-08-05 | 2019-11-13 | 2019-11-04 | GM-VET,210,1 | Brown |
| | Ossmer | Daniel D. (Vet, US Marines, Air Wing, WWII) | 1921-03-05 | 1950-10-28 | 1950-10-25 | GM-P,233,1 | Pifer |
| | Ossmer | Jack Lee (Vet, US Army) | 1945-02-04 | 1995-02-10 | 1995-02-06 | GM-K,56,4 | Smith |
| | Ostrom | Raymond A. (Vet, US Navy, WWII) | 1921-05-16 | 1992-07-17 | 1992-07-05 | NEW-45,24,7A | Zimmerman |
| | Oswald | Ernest Jr. (Vet) | 1936-10-14 | 1985-09-22 | 1985-09-20 | NEW-64,83,1 | Halbritter |
| | Otwell | Raymond Vet, US Army WWI) | 1895-12-02 | 1966-07-20 | 1966-07-17 | GM-C,70,4 | Pifer |
| | Outlaw | Clarence Richard Sr. (Vet, US Air Force) | 1939-07-24 | 2018-06-04 | 2018-05-28 | GM-L,231,1 | Wagner |
| | Overly | Earl Edward (Vet, WW1) | 1889-12-25 | 1934-06-18 | 1934-06-15 | NEW-63,121,1 | Price & Kiger |
| | Owen | Roy A. (Veteran WWI) | 1886-10-15 | 1958-12-30 | 1958-12-27 | GM-Q,214,1 | Pifer |