| Last Name | Given Name / Maiden Name | Birth | Death | Notes |
| O'Brien | Frank | 26 Dec 1851 | 25 Oct 1929 | h/o Laura Mosher O'Brien, p/o Frank, Winnie & Infant Son |
| O'Brien | Infant Son | 19 Jun 1881 | 22 Aug 1881 | s/o Frank & Laura O'Brien |
| O'Brien | Laura Mosher | 7 Oct 1851 | 20 Sep 1903 | s/s Frank O'Brien |
| Ochampaugh | Jennie | 10 Jan 1861 | 16 Jul 1935 | s/s William H. Ochampaugh |
| Ochampaugh | William H. | 5 May 1861 | 19 Oct 1931 | h/o Jennie Ochampaugh, marr 23 Aug 1883 |
| Odendahl | Don | 4 Jul 1946 | 31 May 2019 | 1st wife Mary Denise Ryan, marr 1 Apr 1967, p/o Juli Stephen, Scott; 2nd wife Sherry Lynn Toner, marr 1 Sep 2001 |
| Odendahl | Donald Franklin | 9 Jan 1922 | 7 Feb 2009 | h/o Kathryn "Katie" Meyers Odendahl |
| Odendahl | Elizabeth V. | 1948 | n/d | s/s James Fredrick Odendahl |
| Odendahl | Florence Schoeppner | 11 Jan 1915 | 16 Jan 2011 | s/s George J. Odendahl |
| Odendahl | George J. | 9 Nov 1912 | 30 May 1998 | h/o Florence Schoeppner Odendahl, marr 25 Aug 1937 |
| Odendahl | James Frederick | 3 Aug 1945 | 21 Dec 2001 | h/o Elizabeth V. Odendahl, marr 15 Jul 1972, p/o Kristine, Jodie, Jamie |
| Odendahl | Kathryn "Katie" Meyers | 22 Sep 1925 | 16 Apr 2016 | s/s Donald Franklin Odendahl |
| O'Donnell | Carole L. Kroblen | 1938 | n/d | s/s Patrick Richard O'Donnell |
| O'Donnell | Patrick Richard | 29 Aug 1936 | 6 Nov 2016 | h/o Carole L. Kroblen O'Donnell, marr 18 Apr 1959, p/o Erin, Todd, Shawn |
| Ogilvie | Ada Lilly May | 25 Nov 1907 | 3 Jul 1911 | d/o Donald A. Cannon & Luella Belle Heyman Ogilvie |
| Ogilvie | Twins | 17 Jan 1911 | 7 Mar 1911 | children of Donald A. Cannon & Luella Belle Heyman Ogilvie |
| Ohde | Ann Sturm | 1 Mar 1924 | 24 Aug 2006 | s/s Lester L. Ohde |
| Ohde | Delores Bellinghausen | 26 Apr 1925 | 25 Nov 1985 | s/s Wesley Ohde |
| Ohde | Lester L. | 21 Aug 1918 | 23 Dec 2010 | h/o Ann Sturm Ohde, marr 14 May 1946, p/o Dennis, Darrell, Beverly, Mark |
| Ohde | Wesley | 17 Jul 1915 | 20 Dec 2008 | h/o Delores Bellinghausen Ohde, marr 26 Nov 1946, p/o Betty, Linda, Larry, Barb, Robert |
| O'Herron | Hilaria Ann "Lari" Engelen | 13 Mar 1932 | 13 Feb 2020 | w/o James Edward "Jim" O'Herron, marr 17 Jun 1952, p/o Jane, Terry, Scott, Tom, Kelly |
| O'Herron | James Edward "Jim" | 1 Mar 1932 | 12 May 2024 | s/s Hilaria Ann "Lari" Engelen O'Herron |
| Okken | Henry Anton | 3 Jan 1848 | 26 Sep 1886 | s/o Hermann & Elisabeth Frey Okken |
| Okken | Herman J. | 1845 | 14 Dec 1889 | f/o Hermann Okken |
| Okken | Hermann | 12 Dec 1802 | 22 Oct 1878 | s/o Harm Jans & Gepke Hinderks Hoffmeester Okken |
| Okken | Peter Henrich | 25 Dec 1846 | 26 Jan 1891 | |
| Olberding | Agnes H. Schwarz | 20 Aug 1924 | 28 Jun 1997 | s/s Orville Merle Olberding |
| Olberding | Orville Merle | 21 Dec 1922 | 5 Oct 2004 | h/o Agnes H. Schwarz Olberding, marr 3 Jan 1940, p/o James, Paul, Patricia, Larry |
| Oldham | Catherine Mohler | 10 Jul 1838 | 8 Apr 1905 | 1st marr Henry Clay Reynolds 12 Sep 1861, p/o Cora; 2nd marr William Oldham 1875 |
| Oldham | William | 8 Feb 1834 | 6 May 1914 | 1st marr to Unknown; 2nd marr Catherine Mohller 1875 |
| O'Leary | David John | 18 Mar 1930 | 14 Nov 2006 | h/o Therese Marie "Tess" Heaslip O'Leary, marr 1953, p/o Ann, Nora, Matt, Mark, Jean, Mary, Jean, Patrick Frances |
| O'Leary | Therese Marie "Tess" Heaslip | 7 Jul 1930 | 23 May 2020 | s/s David John O'Leary |
| Olerich | Bertha Woodyard | 26 Oct 1888 | 2 Apr 1982 | w/o William H. Olerich |
| Olerich | Clayton | n/d | 1922 | Inf s/o Frank & Frances Olerich |
| Olerich | Clifford William | 2 Aug 1915 | 31 Mar 1970 | Iowa SGT US Army WWII SS-PH |
| Olerich | Delbert Lee | 1939 | 22 Oct 1965 | h/o Marilyn C. Hike Winkel Olerich |
| Olerich | Donald Eugene | 29 Oct 1928 | 13 Aug 2004 | s/o William H. & Bertha Olerich |
| Olerich | Emma Henrietta Weber | 16 Jun 1910 | 22 May 1998 | w/o Frank C. Olerich |
| Olerich | Evelyn Marie Balk | 7 Jan 1920 | 27 Feb 2009 | s/s Marvin Joseph Olerich |
| Olerich | Frank C. | 6 May 1913 | 28 Jun 1950 | h/o Emma Henrietta Weber Olerich |
| Olerich | Herman Otto | 27 Jul 1891 | 5 Sep 1958 | h/o Theresa Mary Klocke Olerich, marr 1913, p/o Hilda, Clifford, Vern, Frank, Wilbur; 2nd marr Geraldine Schleisman |
| Olerich | Janet Quinn | 10 Nov 1957 | n/d | s/s Rickey Olerich |
| Olerich | John | 31 Dec 1857 | 26 Jan 1931 | h/o Kathryn Schachtner Olerich, marr 8 May 1883, p/o Frank, William, Henry, Mary, Robert, Otto, Herman, Earl, Nettie, Nelley, Lillian |
| Olerich | John | 17 Aug 1914 | 28 Feb 1920 | s/o Robert John & Lydia C. Olerich |
| Olerich | Joleen M. Schelle | 22 Feb 1961 | 13 nat 1988 | p/o Jamie & Greg |
| Olerich | Joseph Earl | 17 Jun 1893 | 4 Aug 1965 | s/o Herman Otto & Theresa Mary Olerich |
| Olerich | Kathryn Schachtner | 1863 | 12 Aug 1930 | w/o John Olerich |
| Olerich | Leo | 21 Feb 1911 | 21 Aug 1941 | h/o Daisy Ellen Pankey Olerich, marr 27 Nov 1934 |
| Olerich | Lydia C. Johnson | 9 Aug 1886 | 3 Jan 1971 | s/s Robert John Olerich |
| Olerich | Marilyn C. Hike Winkle | 1942 | n/d | s/s Delbert Lee Olerich |
| Olerich | Marvin Joseph | 29 May 1919 | 18 Mar 2005 | h/o Evelyn Marie Balk Olerich, p/o Kay, Keith, Linda, Kristy, Dennis, Dean, Daniel |
| Olerich | Milo Wayne | 22 May 1924 | 11 Jul 1965 | h/o Janice Lena Reis Huisenga, marr 7 Sep 1949, p/o Allan, Linn Rick, Cathy, Dean |
| Olerich | Raymond E. | 28 Mar 1918 | 23 Feb 1919 | s/o William H. & Bertha Olerich |
| Olerich | Rickey | 27 Feb 1956 | 13 Nov 2019 | h/o Janet Quinn Olerich, marr 12 Jun 1976, p/o Samantha & Abbey |
| Olerich | Robert John | 4 Sep 1889 | 8 Dec 1942 | h/o Lydia C. Johnson Olerich, p/o John, Violet, Bernice, Gilbert, Edward, Maurice, Pearl, Rosemarie |
| Olerich | Theresa Mary Klocke | 2 Mar 1891 | 25 Feb 1941 | 1st w/o Herman Otto Olerich |
| Olerich | Vern Charles | 8 Jun 1921 | 27 May 1953 | s/o Herman Otto & Theresa Mary Olerich; RM3 USNR WWII |
| Olerich | Violet May | 12 Dec 1918 | 18 Mar 1919 | d/o Robert John & Lydia C. Olerich |
| Olerich | Wilbur John | 20 Jul 1917 | 8 Jun 1919 | s/o Herman Otto & Theresa Mary Olerich |
| Olerich | William H. | 18 Nov 1887 | 11 Dec 1950 | h/o Bertha Woodyard Olerich, marr 11 Oct 1910, p/o Archie, Virgil, Donald, Wilma, Raymond |
| Olesen | Doris Arlene Schroeter | 5 Oct 1918 | 10 Oct 2001 | s/s Vorgelious Victor "Virgil" Olesen |
| Olesen | Eva Nelson | 7 Feb 1893 | 4 Nov 1984 | s/s Ole Marinus Olesen |
| Olesen | Josephine M. | 14 Feb 1917 | 16 Feb 1917 | d/o Ole Marinus & Eva Olesen |
| Olesen | Ole Marinus | 16 Dec 1891 | Feb 1965 | h/o Eva Nelson Olesen, marr 10 Sep 1913, p/o Vergelius, Virginia, Josephine, Gladys |
| Olesen | Vorgelious Victor "Virgil" | 21 Jun 1914 | 10 May 2004 | h/o Doris Arlene Schroeter Olesen |
| Oleson | Donald Eugene | 7 Jan 1949 | 20 May 2017 | h/o Shari R. Johnson Oleson, marr 1 May 1971, p/o Suzanne & Jeffrey |
| Oleson | Shari R. Johnson | 26 May 1950 | 23 Jun 2018 | s/s Donald Eugene Oleson |
| Olsen | Arley John | 18 Dec 1910 | 5 Apr 1959 | h/o June Gray Swart Olsen |
| Olsen | June Gray Swart | 7 Jun 1913 | 5 Oct 1995 | s/s Arley John Olsen |
| Onan | John Clark | 20 Jun 1843 | 9 Apr 1935 | h/o Phoebe Jane Winters, marr 18 Oct 1860 |
| Onan | Phooebe Jane Winters | Mar 1843 | 17 Mar 1932 | w/o John Clark Onan |
| O'Neal | Charles Pierce | 1853 | 1938 | h/o Emma Tower O'Neal |
| O'Neal | Emma Tower | 1857 | 21 May 1930 | s/s Charles Pierce O'Neal |
| O'Neal | Harvey | n/d | n/d | per WPA |
| Onken | Albert C. | 19 Jan 1873 | 21 Feb 1965 | h/o Mary Honora Best Onken, marr 2 Jun 1897, p/o LeRoy, Lavina, Eunie, Leone |
| Onken | August Dederick | 8 Sep 1865 | 31 May 1937 | h/o Emma A. Wenck Onken, marr 1 Mar 1888, p/o Bessie, William, Elmer, Lester, infant son |
| Onken | Bobby | | 1922 | Inf s/o Edward & Rosetta Onken |
| Onken | Baby Son | | 1922 | s/o Edward & Rosetta Onken |
| Onken | Donald Lee "Swede" | 22 Jan 1932 | 16 Sep 2002 | s/o Lester & Laura Onken; US Army |
| Onken | Emma A. Wenck | 10 Oct 1866 | 1 May 1944 | w/o August Dederick Onken |
| Onken | Ethel | | 3 Sep 1930 | Inf d/o Edward & Rosetta Onken |
| Onken | Ethel E. | 13 Jul 1900 | 5 Mar 1901 | d/o William Onken |
| Onken | Glenness Elmer | 12 Jul 1927 | 22 Aug 2006 | h/o Shirley Ann Lyons Onken, marr 14 Feb 1953, p/o Sally & Scott |
| Onken | Infant Son | n/d | 23 Jun 1896 | s/o A.D. & E. M. Onken, aged 3 dys |
| Onken | Laura Elizabeth Albers | 3 May 1905 | 4 Feb 1983 | s/s Lester Dedrick Onken |
| Onken | Lavine Loretta | 12 Nov 1912 | 21 Jan 1913 | d/o Albert C. & Mary Honora Onken |
| Onken | Lawrence Herbert | 17 Aug 1946 | 13 Apr 2021 | h/o Susan Kay Husman, p/o Ryan |
| Onken | Lena Mandelkow | 10 Jan 1870 | 26 Jan 1936 | w/o William Onken |
| Onken | LeRoy James | 14 Feb 1901 | 26 Apr 1916 | s/o Albert C. & Mary Honora Onken |
| Onken | Lester Dedrick | 6 Jun 1902 | 4 Apr 1945 | h/o Laura Elizabeth Albers Onken, mar 14 Jan 1925, p/o Robert, Donald, Marjorie, Leland |
| Onken | Mary Honora Best | 19 Jan 1878 | 3 Aug 1960 | s/s Albert C. Onken |
| Onken | O. Dederich | 17 Sep 1835 | 21 Feb 1911 | h/o theda Margaretha Mehrings Onken, p/o Albert, William, August, Grace, Hannah, Emma |
| Onken | Shirley Ann Lyons | 28 Sep 1928 | 24 Oct 2014 | s/s Glenness Elmer Onken |
| Onken | Susan Kay Hausman | 1 Apr 1951 | n/d | s/s Lawrence Herbert Onken |
| Onken | Theda Margaretha Mehrings | 15 Jan 1840 | 30 Jun 1898 | s/s O. Dederich Onken |
| Onken | William | 20 Nov 1870 | 8 Jan 1925 | h/o Lena Mandelkow Onken, 21 Mar 1894, p/o Viola, ed, arthur, Dorothy, Edw., Walter, Clifford, Lillian, Ethel |
| Origer | Brian | n/d | n/d | s/s Marlene Marian berger Origer |
| Origer | Marlene Marian Berger | 30 Apr 1953 | 28 Oct 2016 | w/o Brian Origer, marr 5 May 1990 |
| Ortner | Michael John | 3 Apr 1966 | 12 Apr 2019 | p/o Alex |
| Osborn | Roger L. | 27 Jul 1935 | 27 Feb 1980 | |
| Osborne | Abbie Hefferman | 1867 | 1952 | w/o Edard James Osborne |
| Osborne | Abbie Luella | 24 Jan 1871 | 17 Nov 1905 | 1st w/o John E. Osborne, p/o John Lyle & Glenard |
| Osborne | Anna Orcutt Dutton | 30 Nov 1876 | 6 Sep 1924 | s/s Nicholas Wellington |
| Osborne | Edna Mae Rabb | 10 Sep 1900 | 20 Feb 1988 | s/s Edward Eugene Osborne |
| Osborne | Edward Eugene | 25 Aug 1901 | 19 Feb 1966 | h/o Edna Mae Rabb Osborn |
| Osborne | Edward James | 1 Mar 1868 | 13 Mar 1945 | h/o Abbie Hefferman Osborne |
| Osborne | Elizabeth Simons | Apr 1855 | 7 Jan 1920 | 2nd w/o John E. Osborne, marr 24 Nov 1911 |
| Osborne | Mageruite Gretchen Kalkuski | 2 Feb 1892 | 5 Oct 1919 | w/o William F. Osborne |
| Osborne | Nellie May | 14 Jan 1875 | 25 Jan 1877 | w/o Thomas Osborne |
| Osborne | Nicholas Wellington | 4 Jun 1875 | 11 Aug 1944 | h/o Anna Orcutt Dutton Osborne, marr 25 Jan 1905, p/o Gerald & Duane |
| Osborne | Thomas | 11 Jan 1848 | 6 Mar 1891 | h/o Nellie May Osborne, p/o Nichols W. & Robert |
| Osborne | William F. | 14 Jun 1877 | 4 Feb 1956 | h/o Mageruite Gretchen Kalkuski Osborne, marr 24 Aug 1912, p/o Marjorie, Beulah, grealdine |
| Osborne | Glenard | 1903 | Jun 1922 | s/o John E. & Abie L. Osborne |
| Osten | Alfred August | 1887 | 1950 | h/o Hilda C. Miller Osten, s/s Hilda & Maxine Osten |
| Osten | Hilda C. Miller | 28 Jun 1891 | 26 Dec 1975 | s/s Alfred August & Maxine Osten |
| Osten | Martha Marie Russell | 6 Aug 1918 | 14 Dec 2000 | s/s Wayn Millard Osten & Reed Barnes, Jr. |
| Osten | Maxine Thekla | 7 Nov 1918 | 1 Jul 1933 | d/o Alfred & Hilda Osten; s/s Alfred & Hilda Osten |
| Osten | Wayne Millard | 30 Aug 1916 | 4 Dec 1991 | h/o Martha Marie Russell Osten; s/s Martha Marie Russell Osten & Reed Barnes Jr. |
| Oswald | Darlene Emma Neumayer | 12 Nov 1930 | 20 Dec 2016 | s/s Paul Henry Oswald |
| Oswald | Paul Henry | 4 Apr 1924 | 11 Jan 2017 | h/o Darlene Emma Neumayer Osward, marr 21 Jun 1950, p/o Danny, Daryl, Donald, Deanne, David |
| O'Tool | Clarice F. | 21 Jan 1929 | n/d | s/s Donald Edward O'Tool |
| O'Tool | Donald Edward | 15 Sep 1928 | 10 Jan 2020 | h/o Clarice F. O'Tool, marr 15 Sep 1949, p/o Kathryn, Donita, Julie |
| O'Tool | Edward | 31 Aug 1894 | 26 Aug 1960 | h/o Nettie K. Olerich O'Tool; Iowa SGT Co I 350 Inf 88 Div WWI |
| O'Tool | Nettie K. Olerich | Aug 1896 | 17 Mar 1969 | w/o Edward O'Tool |
| O'Tool | Richard Andrew "Dick" | 6 Jul 1940 | 13 Feb 2022 | |
| Otto | Clair | 12 Jan 1933 | 9 Aug 2023 | s/s Lou Ann Wolterman Otto |
| Otto | H. William | 23 May 1880 | 12 May 1959 | h/o Marie Auguste Finnern Otto, p/o Walter, Herm, Flora, Harriet, Wilma |
| Otto | Lou Ann Wolterman | 4 Feb 1933 | 19 Jan 2022 | w/o Clair Otto, married 27 Feb 1954, p/o Laura, Sheryl, Barb, Steve |
| Otto | Marie Auguste Finnern | 21 Jun 1880 | 29 Mar 1959 | s/s H. William Otto |
| Owen | Connie L. | 18 Oct 1946 | 21 Aug 1992 | d/o Lewis C. & Frances M. Owen |
| Owen | Frances "Fran" Lehrter | 1 Jun 1928 | 8 Oct 2024 | s/s Lewis C. Owen |
| Owen | Lewis C. | 15 Dec 1923 | 7 Aug 1995 | h/o Frances M. Owen, marr 13 Nov 1946; US Air Force WWII |
| Owens | Elizabeth | Apr 1836 | 1921 | w/o John Owens |
| Owens | John | 3 Mar 1826 | 24 Mar 1898 | h/o Elizabeth Owens |
