- O'Boyle, Beverly A. - 2016
- O'Brien, Byron C. "Pat" - 1971
- O'Brien, Charles P. III - 2006
- O'Brien, Mrs. Mary E. - 1927
- O'Conner, Frank - unknown
- O'Conner, George Franklin - 1960
- O'Conner, Gerald Wendell - 2001
- O'Connor, Mrs. Anna Harriet - 1940
- O'Connor, Clara A. (Madden) - 1988
- O'Connor, Pfc Floyd C. - 1945
- O'Connor, Hazel A. - unknown
- O'Connor, Helen T. (Helping) - 1988
- O'Connor, Henry - unknown
- O'Connor, Minnie (Moore) - unknown
- O'Connor, Paul - 1943
- O'Connor, Paul G. - unknown
- O'Connor, T. E. - 1946
- O'Connor, Walter F. - 1989
- O'Keefe, Gerald W. - 2006
- O'Leary, John Sr - 1975
- O'Neal, Howard Wayne - 2008
- O'Neal, Maple G. (Carnahan) - 1975
- O'Reilley, Thomas J - 1918
- O'Reilly, Rev. S. P. - 1957
- O'Riordan, Joyce Ellen (Johnson) - 2016
- O'Shaughnessey, Mrs. Lucille D. - 2009
- Oakley, Col. B. W. - 1873
- Oakley, Rev. Charles, Sr. - 1940
- Oakley, Col. Chauncey B. - 1903
- Oakley, Mrs. Emily A. - 1863
- Oakley, Mrs. Harriet - 1878
- Oaks, Norman - 2012
- Obear, Mrs. Emma J. - 1959
- Ober, John - no date
- Ober, (Larry) Gene - 2013
- Oberley, Diana "Lynne" (Ellis) - 2020
- Oberlin, Mrs. Mildred L. - 1990
- Oberlin, Rosellen M. (LaPradd) - 2017
- Ochiltree, James A. - 1939
- Ochoa, Eleanor M. (Torres) - 2018
- Ochoa, Hector - 2017
- Ockerman, Nancy E. (Wade) Mitchell - 1942
- Odier, Barbara Ann (Willen) - 2017
- Odle, Larry Dean - 2002
- Odom, Mrs. Frieda A. - 1972
- Oehler, Jerald L. - 2019
- Oeschle, Sara A. (Putman) - 1967
- Oetting, Albert A. - 2017
- Oetting, Clarence G. - 2016
- Oetting, Lois M. (Lynch) - 2019
- Offutt, Harry C. - 1957
- Ogden, Robert - 2003
- Ogg, Vonda Lee (Macklin) - 2019
- Ogle, A. B. - 1900
- Ogle, Mrs. Letha - 1940
- Oglesbee, John H. - 2018
- Ohler, Miss Christine A. - 2017
- Ohneck, Miss Karen Jean - 2017
- Oldelia, Sr. M. (nee Nesswald) - 1974
- Olinger, Budd D. - 2019
- Olive, George S. - 1962
- Olive, James - 1940
- Oliver, Mrs. John - 1891
- Olsen, Lyle M. - 2001
- Olvera, Gavino C - 2018
- Olvey, William P. - 1891
- Olwin, Ruth E. (Broom) - 2006
- Oman, James H. - 1984
- Omlor, Herman O. - 1974
- Omspach, Robert W. - 1972
- Oncheck, Tina L. (Glass) - 2006
- Opatz, Emma A. (Perry) - 1942
- Opliger, Alvin E. - 1990
- Oplinger, Arthur R. - 1988
- Oppy, Edna Janette (Boughton) - 1951
- Orcutt, Gerald Duane - 1969
- Orcutt-Fulk, Sarah Lue (Miller) - 2006
- Orender, Joshua - 1889
- Orr, Berkey D. - 1957
- Orr, Emmet - 1954
- Orr, Minnie E. (Smith)
- Orth, John Adams - 1940
- Ortiz, Jose Guiterrez - 1943
- Ortiz, Luz Maria (Torres) - 2017
- Ortiz, Margaret Vickers (Funk) - 2004
- Ortman, Conrad - 1916
- Orwig, Victor B. - 1986
- Osborn, Deborah Kaye (Bridges) - 2004
- Osborn, Ned P. - 2017
- Osborn, Wayne Dennis - 2019
- Osborne, Eugene F. - 2006
- Osborne, George M. - 1895
- Osborne, Vicki Sue (Faulkner) - 1985
- Osborne, Zachary - 1881
- Osbun, Aaron C. - 1987
- Osbun, Deloris M. (Grobis) - 1988
- Osbun, Mrs. Helen J. - 1989
- Osbun, Maynard C - 2007
- Osbun, Stephen W. - 1965
- Oser, Alan R - 2018
- Oster, John - 1967
- Osterheld, Mary (Limecooly) - 1940
- Osterholt, Henry J. - 1997
- Osterman, George W. - 1962
- Ostman, Charles - 1891
- Ostman, Richard E - 2018
- Ostrander, Barbara Ann (Manning) - 2014
- Oswald, Thelma T. (McNabb) - 1979
- Oswalt, Mildred Delores - 1940
- Oswalt, Patricia A. (VanMeter) - 2006
- Oswalt, Robert M. - 1992
- Ott, Kenneth K. - 2019
- Ott, Ruth (Owen) - 2019
- Ottinger, Geneva A. (Shields) - 2000
- Otto, Mrs. Katherine - 1940
- Ousley, Elsie M. (Hunter) - 2017
- Ousley, Oscar E. - 2018
- Outcalt, Faythe M. (Bixler) - 2017
- Oval, Helen Louise - 1917
- Overholser, Betty J. (Sheets) - 2011
- Overholser, Mrs. Ruth - 1969
- Overman, Catherine (Moeder) - 1940
- Overman, Mrs. Elia E. - 1997
- Overman, Mrs. Mildred - 1934
- Overmeyer, John T. - 2004
- Overmier, Bertha (Aschliman) - 1972
- Overpeck, Clara (Parrett) - 1935
- Overstreet, G. M. Jr. - 1897
- Overton, Hazel L. - 2016
- Ovitt, Jeremiah E. - 2018
- Owen, Mrs. Anna Cathern - 1940
- Owen, AnnJeanette (Amkney) - 2019
- Owen, Darryl Jay - 2007
- Owen, Robert Dale - 1877
- Owendorf, Miss Ophelia - 1973
- Owens, Bessie (Kirby) - 1978
- Owens, Charles E. - 2019
- Owens, Donna Carol - 2018
- Owens, Holly A. - 2019
- Owens, John - 1890
- Owens, Robert L. Jr. - 2006
- Owens, Tyler A. - 2018
- Oyer, Benjamin - 1940