| Henry | O'Blenness | 85 | OH | INF | F | SGT | Athens | |
| Michael | O'Boyle | 156th | NY | INF | A | Montgomery | ||
| William | A | O'Brian | 4 | OH | CAV | I | 1SGT | Wayne |
| T | O'Brian | 11 | OH | INF | G | PVT | Stark | |
| William | E. | O'Brian | 142 | OH | INF | F | PVT | Knox |
| James | O | O'Brien | 2 | OH | MIL | E | PVT | Darke |
| Patrick | O'Brien | 184 | OH | INF | U | PVT | Ross | |
| John | O'Brien | 123 | OH | INF | F | PVT | Wyandot | |
| Cornelious | O'Brien | 152 | OH | INF | I | CPL | Darke | |
| Michael | O'Brien | 68th | IL | INF | E | Montgomery | ||
| John | O'Brien | 4 | OH | INF | A | PVT | Marion | |
| William | O'Brien | 14th | MI | INF | B | Montgomery | ||
| Thomas | O'Brien | 102 | OH | INF | H | PVT | Wayne | |
| William | O'Brien | 18 | US | INF | B | CPL | Franklin | |
| Lewis | O'Bryant | 33 | OH | INF | G | PVT | Ross | |
| Peter | O'Cain | 22 | OH | INF | E | CAPT | Preble | |
| Michael | O'Connell | 101 | OH | INF | I | PVT | Seneca | |
| Dennis | O'Conner | 72 | OH | INF | K | PVT | Stark | |
| Edward | O'Conner | 67 | OH | INF | H | MUS | Wood | |
| John | O'Conner | 6 | OH | CAV | K | PVT | Geauga | |
| Jacob | O'Conner | 33 | OH | INF | H | PVT | Ross | |
| John | O'Connor | 36 | OH | INF | K | PVT | Erie | |
| Cornelius | O'Connor | 8 | OH | INF | B | PVT | Hancock | |
| Cornelius | O'Connor | 197 | OH | INF | F | PVT | Seneca | |
| Thomas | A | O'Connor | 39 | OH | INF | G | PVT | Seneca |
| John | O'Connor | 61 | MA | INF | G | PVT | Huron | |
| Philip | H | O'Day | 133 | OH | INF | D | PVT | Franklin |
| John | O'Day | 113 | OH | INF | G | PVT | Pickaway | |
| Hiram | O'Dell | 25 | OH | INF | E | PVT | Sandusky | |
| Bennager | O'Dell | 25 | OH | INF | E | PVT | Sandusky | |
| Morris | O'Donnell | 32nd | OH | INF | G | Montgomery | ||
| William | H | O'Hara | 180 | OH | INF | I | PVT | Hancock |
| John | C | O'Hara | 1 | OH | CAV | E | CAPT | Pickaway |
| James | O'Hara | 140 | PA | INF | B | PVT | Erie | |
| James | O'Hara | 122 | OH | INF | I | CPL | Erie | |
| James | O'Hara | 111th | NY | INF | H | Montgomery | ||
| Nathan | O'Hara | 184 | OH | INF | E | PVT | Franklin | |
| Thomas | J | O'Hara | 21 | OH | INF | B | MUS | Hancock |
| George | W | O'Hare | 62 | OH | INF | C | CPL | Hocking |
| Charles | E | O'Harra | 4 | OH | CAV | A | PVT | Franklin |
| Harvey | B | O'Harra | 182 | OH | INF | C | 2LT | Pickaway |
| J | T | O'Harra | 95 | OH | INF | C | PVT | Franklin |
| William | C | O'Harra | 50 | OH | INF | C | 1LT | Preble |
| John | O'Hea | 50th | OH | INF | D | Montgomery | ||
| Phillip | F | O'Hearn | 148 | OH | INF | A | PVT | Franklin |
| Patrick | O'Mahley | 22nd | IL | INF | K | PVT | Montgomery | |
| Thomas | H | O'neal | 88 | OH | INF | B | PVT | Pickaway |
| John | O'Neal | 197 | OH | INF | K | PVT | Stark | |
| Barton | O'Neal | 123 | OH | INF | A | PVT | Wyandot | |
| Samuel | N | O'Neal | 88 | OH | INF | G | PVT | Pickaway |
| Stewart | O'Neil | 6 | OH | CAV | L | PVT | Erie | |
| Michael | O'Neil | 60 | OH | INF | E | PVT | Erie | |
| John | O'Neill | 8th | IL | INF | B | Montgomery | ||
| Bartholomew | O'Neill | 38 | US | INF | I | Stark | ||
| Michael | O'Neill | 1 | OH | LART | F | PVT | Erie | |
| Peter | O'Riley | 8th | PA | CAV | I | PVT | Montgomery | |
| William | O'Shaughnessy | 14th | MI | INF | I | Montgomery | ||
| Oliver | S.T. | Oaks | 151 | OH | INF | H | CPL | Hocking |
| Josiah | Oaks | 31 | OH | INF | A | PVT | Erie | |
| Henry | S | Oaks | 21 | OH | INF | H | PVT | Hancock |
| John | Oates | 9 | OH | CAV | E | PVT | Wood | |
| John | G | Oates | 3 | OH | CAV | B | 2LT | Huron |
| Harvy | E | Oatley | 5 | US | ART | G | SGT | Hocking |
| John | Obee | 100 | OH | INF | D | PVT | Lucas | |
| Adam | Obenour | 110 | OH | INF | G | PVT | Hancock | |
| Jacob | Ober | 193 | OH | INF | F | PVT | Erie | |
| William | Oberdier | 46 | OH | INF | B | CPL | Marion | |
| Henry | Oberhaus | 186 | OH | INF | E | PVT | Sandusky | |
| Jacob | Oberholser | 164 | OH | INF | F | Summit | ||
| Joseph | Oberla | 103 | OH | INF | F | PVT | Fulton | |
| Joseph | Oberlander | 10 | OH | CAV | UNASSIGNED | PVT | Wyandot | |
| James | Oberlander | 91 | IN | INF | K | PVT | Wyandot | |
| Morris | Oberlin | 123 | OH | INF | F | PVT | Wyandot | |
| Isaac | Oberlin | 162 | OH | INF | C | PVT | Stark | |
| Obed | Oberlin | 162 | OH | INF | E | PVT | Stark | |
| Frank | L | Oberly | 103 | OH | INF | F | PVT | Wood |
| Philip | A | Obermeyer | 169 | OH | INF | K | 2LT | Sandusky |
| Simon | P | Obermyer | 72 | OH | INF | B | PVT | Hancock |
| Gilbert | Oberton | 113 | IL | INF | G | PVT | Wayne | |
| Charles | H | Obetz | 186 | OH | INF | B | PVT | Franklin |
| J | Oblinger | 72 | OH | INF | H | Hamilton | ||
| William | M | Obney | 79 | IN | INF | K | Stark | |
| Charles | Oborn | 26 | OH | INF | F | PVT | Columbiana | |
| Michael | Obrien | 23 | OH | INF | H | PVT | Delaware | |
| George | W | Oby | 6 | US | CAV | Stark | ||
| William | Ochschim | 58th | OH | INF | D | PVT | Montgomery | |
| Edward | Odell | 95 | OH | INF | I | PVT | Franklin | |
| Martin | V.B. | Odell | 46 | OH | INF | C | PVT | Franklin |
| Moses | Odell | 95 | OH | INF | I | PVT | Franklin | |
| Henry | Oehler | 13 | OH | INF | A | PVT | Stark | |
| John | Oesch | 107 | OH | INF | D | PVT | Columbiana | |
| Jacob | Oesterlin | 198 | OH | INF | F | PVT | Huron | |
| Frederick | Oesterly | 10 | OH | INF | K | PVT | Delaware | |
| Albert | Offet | 10 | OH | CAV | G | PVT | Sandusky | |
| John | Q | Ogan | 51 | OH | INF | D | SGT | Erie |
| Oliver | Ogan | 67 | OH | INF | I | PVT | Ross | |
| Thompson | Ogden | 133 | NY | INF | G | CAPT | Franklin | |
| Amos | Erwin | Ogden | 164 | OH | INF | K | PVT | Seneca |
| George | S | Ogden | 25 | OH | INF | G | CPL | Seneca |
| Edward | P | Ogden | 149 | OH | INF | E | PVT | Ross |
| David | Ogden | 63 | OH | INF | B | PVT | Ross | |
| David | D | Ogden | 35 | OH | INF | E | PVT | Preble |
| John | H | Ogden | 162 | OH | INF | A | PVT | Stark |
| Charles | D | Ogden | 152 | OH | INF | K | PVT | Franklin |
| Herbert | G | Ogden | 101 | OH | INF | H | 1LT | Seneca |
| Edmon | Ogden | 8 | MI | INF | I | PVT | Erie | |
| Jerome | Ogg | 49 | OH | INF | A | CPL | Hancock | |
| George | Ogg | 49 | OH | INF | K | PVT | Seneca | |
| Alexander | J | Ogle | 72 | OH | INF | D | PVT | Sandusky |
| David | Ogle | 108 | OH | INF | I | CPL | Ross | |
| Thomas | C | Oglesbee | 46 | OH | INF | K | PVT | Paulding |
| John | F | Oglevee | 98 | OH | INF | 1LT | Franklin | |
| Artemas | Oglevie | 88 | OH | INF | Franklin | |||
| Ezra | G | Ohl | 196 | OH | INF | A | PVT | Geauga |
| Larean | Ohlinger | 13 | WV | INF | D | Franklin | ||
| Oluf | C | Ohlson | 4 | IN | CAV | M | 2LT | Lucas |
| George | Oiler | 27 | OH | INF | H | PVT | Pickaway | |
| Samuel | Oiler | 173 | OH | INF | G | Ross | ||
| Joseph | Okuly | 124 | OH | INF | D | PVT | Henry | |
| Jacob | Olbert | 88 | OH | INF | H | PVT | Franklin | |
| Henry | Oldem | 196 | OH | INF | F | Preble | ||
| Henry | Oldendorph | 16 | IL | CAV | K | Franklin | ||
| Caleb | Older | 144 | OH | INF | I | PVT | Wood | |
| Barnett | Older | 68 | OH | INF | I | PVT | Wood | |
| Silas | S | Older | 68 | OH | INF | I | PVT | Wood |
| Samuel | Oldfather | 54 | OH | INF | E | PVT | Preble | |
| George | B | Oldfield | 182 | OH | INF | B | PVT | Fulton |
| Charles | O | Oldfield | 96 | OH | INF | B | 1LT | Wyandot |
| Henry | C | Oldfield | 68 | OH | INF | K | PVT | Fulton |
| George | W | Oldfield | 178 | OH | INF | G | CPL | Stark |
| John | Oldfield | 75 | OH | INF | UNASSIGN | PVT | Hocking | |
| Allen | W | Oldfield | 90 | OH | INF | G | PVT | Hocking |
| Charles | T | Oldfield | 4 | OH | INF | F | CPL | Stark |
| William | M | Oldham | 12 | OH | CAV | D | PVT | Franklin |
| Joshua | G | Oldham | 96 | OH | INF | A | PVT | Delaware |
| Isaac | Oldham | 44th | OH | INF | B | PVT | Montgomery | |
| Albert | H | Oldham | 67 | OH | INF | G | CPL | Stark |
| Thomas | Oldham | 78 | OH | INF | C | PVT | Franklin | |
| Asbury | B | Oldroyd | 16 | OH | INF | C | PVT | Wayne |
| Wilbur | F | Oldroyd | 169 | OH | INF | D | PVT | Wayne |
| Elmer | G | Oldroyd | 14 | IA | INF | G | SGT | Wayne |
| Jos | Edwin | Olds | 130 | OH | INF | H | PVT | Pickaway |
| Chauncey | Olds | 3 | OH | CAV | L | PVT | Delaware | |
| Sanford | Olds | 121 | OH | INF | D | PVT | Delaware | |
| Henry | C | Olds | 145 | OH | INF | F&S | MAJ | Delaware |
| Benjamin | F | Olds | 128 | OH | INF | E | PVT | Portage |
| Henry | Olds | 144 | OH | INF | C | PVT | Wood | |
| Andrew | Olds | 111 | OH | INF | K | PVT | Wood | |
| Henry | Olds | 1 | OH | LART | C | CPL | Geauga | |
| Gilbert | O | Olds | 55 | OH | INF | G | CPL | Paulding |
| Henry | Olds | 3 | OH | CAV | L | PVT | Ottawa | |
| Hubert | B | Olds | 55 | OH | INF | G | CPL | Seneca |
| Lewis | Olendorf | 88 | OH | INF | K | PVT | Franklin | |
| George | Olenhouse | 2 | MA | CAV | A | BUGL | Erie | |
| Andrew | Oleson | 2 | MN | INF | I | PVT | Hamilton | |
| Ephriam | Olinger | 162 | OH | INF | G | PVT | Stark | |
| William | C | Olinger | 2 | OH | HART | B | PVT | Erie |
| George | W | Oliver | 5 | OH | INF | G | PVT | Erie |
| John | T | Oliver | 155 | OH | INF | A | 2LT | Pickaway |
| Levi | Oliver | 42 | IL | INF | A | PVT | Franklin | |
| James | B | Oliver | 123 | OH | INF | F | PVT | Wyandot |
| Alexander | S | Oliver | 34 | OH | INF | G | SGT | Erie |
| Allen | W | Oliver | 187 | OH | INF | C | PVT | Darke |
| John | Oliver | 26 | OH | INF | I | CPL | Darke | |
| Ezra | R | Oliver | 145 | OH | INF | F | SGT | Huron |
| Francis | Oliver | 115 | OH | INF | K | PVT | Stark | |
| J | W. | Oliver | 180 | OH | INF | F | PVT | Hocking |
| William | M | Oliver | 174 | OH | INF | B | PVT | Franklin |
| Francis | M | Oliver | 51 | OH | INF | K | PVT | Darke |
| Phillip | B | Oliver | 144 | OH | INF | A | MUS | Hancock |
| Benjamin | F | Ollom | 36 | OH | INF | H | PVT | Pickaway |
| James | Olmstead | 189 | OH | INF | B | PVT | Lucas | |
| Theodore | Olmstead | 130 | OH | INF | A | PVT | Fulton | |
| David | N | Olmstead | 189 | OH | INF | B | PVT | Lucas |
| Charles | F | Olmstead | 96 | OH | INF | F | PVT | Delaware |
| Sanford | A | Olmstead | 145 | OH | INF | C | PVT | Delaware |
| Charles | Olmsted | 164 | OH | INF | I | 1LT | Hancock | |
| Nelson | Olmsted | 1 | OH | HART | M | PVT | Huron | |
| Wilson | Olney | 40 | OH | INF | A | PVT | Pickaway | |
| George | B | Olney | 111 | OH | INF | D | PVT | Wood |
| Joel | Olney | 96 | OH | INF | G | TMST | Delaware | |
| John | A | Olney | 4 | OH | INF | C | PVT | Delaware |
| Jacob | F | Oman | 21 | OH | INF | B | CPL | Hancock |
| Henry | F | Oman | 134 | OH | INF | H | PVT | Hancock |
| Samuel | Oman | 50 | OH | INF | D | PVT | Hancock | |
| Wesley | B F | Oman | 134 | OH | INF | E | PVT | Hancock |
| Ephriam | Oman | 29 | OH | INF | E | PVT | Hancock | |
| Jacob | Omlor | 164 | OH | INF | I | PVT | Hancock | |
| Josiah | Omo | 58 | OH | INF | I | PVT | Pickaway | |
| Jacob | Omwag | 101 | OH | INF | C | PVT | Huron | |
| Jeremiah | L | Omwake | 101 | OH | INF | I | PVT | Henry |
| John | B | Onkrant | 22nd | KY | INF | G | PVT | Montgomery |
| Edward | Onsey | 20 | OH | INF | D | PVT | Delaware | |
| Thomas | Onstott | 16 | OH | INF | B | PVT | Wayne | |
| David | Onweller | 67 | OH | INF | I | PVT | Fulton | |
| Samuel | Onweller | 67 | OH | INF | I | CPL | Fulton | |
| James | Onweller | 68 | OH | INF | A | PVT | Fulton | |
| Jasper | D | Ooley | 14 | IL | INF | D | PVT | Wyandot |
| John | S | Opdyke | 163 | OH | INF | H | PVT | Seneca |
| Wilboughby | F | Opp | 148 | PA | INF | H | PVT | Hancock |
| Jacob | Opp | 180 | OH | INF | K | PVT | Wyandot | |
| Abraham | E | Opperheimer | 17 | IL | CAV | K | CPL | Sandusky |
| Henry | Opperman | 3 | PA | HART | I | PVT | Erie | |
| Henry | Opt | 49 | OH | INF | C | PVT | Seneca | |
| Amos | J | Orahood | 121 | OH | INF | I | PVT | Marion |
| Henry | Y | Oram | 21 | OH | INF | G | PVT | Hancock |
| Newell | E | Orcutt | 9 | OH | LART | INDEPT | PVT | Geauga |
| George | W | Orders | 182 | OH | INF | E | CPL | Franklin |
| Jonas | Orders | 113 | OH | INF | C | CPL | Franklin | |
| James | Ordway | 100 | OH | INF | A | PVT | Wood | |
| Francis | M | Orebaugh | 75 | OH | INF | G | PVT | Preble |
| B | F | Orem | 1 | MD | INF | K | Franklin | |
| Ephraim | G | Orenbaugh | 153 | OH | INF | K | PVT | Franklin |
| John | Organ | 1 | MI | CAV | E | SGT | Lucas | |
| Allen | D | Orlen | 27 | US | CT | I | PVT | Huron |
| Andrew | J | Orm | 8 | OH | INF | A | PVT | Hancock |
| Wilson | S | Orme | 49 | OH | INF | K | CPL | Henry |
| Doran | H | Ormes | 9 | VT | INF | D | Summit | |
| Oliver | Orn | 17 | OH | INF | D | PVT | Hocking | |
| Elijah | Orndorf | 17 | OH | INF | F | Athens | ||
| John | Orner | 164 | OH | INF | K | PVT | Seneca | |
| William | Orobaugh | 54 | OH | INF | B | PVT | Preble | |
| William | Orr | 195 | OH | INF | I | PVT | Preble | |
| John | C | Orr | 156 | OH | INF | A | PVT | Preble |
| Oscar | Orr | 125 | OH | INF | K | PVT | Athens | |
| Robert | W | Orr | 57 | PA | INF | I | CAPT | Summit |
| Thomas | Orr | 4 | IL | INF | E | SGT | Seneca | |
| Jeremiah | Orr | 149 | OH | INF | SGT | Ross | ||
| Harvey | Orr | 22 | OH | INF | G | PVT | Ross | |
| Amos | C | Orr | 10 | OH | LART | BATT | PVT | Preble |
| Smith | Orr | 169 | OH | INF | D | PVT | Wayne | |
| John | Orr | 43 | OH | INF | H | PVT | Stark | |
| James | T | Orr | 169 | OH | INF | D | CPL | Wayne |
| William | Orr | 114 | OH | INF | B | PVT | Franklin | |
| Matthew | T | Orr | 104 | OH | INF | C | PVT | Columbiana |
| Gilbert | Orr | 22 | OH | INF | G | PVT | Ross | |
| Londias | Orr | 198 | OH | INF | G | PVT | Marion | |
| James | H | Orr | 108 | OH | INF | F | CAPT | Franklin |
| Joseph | Orr | 8 | OH | INF | G | PVT | Sandusky | |
| James | Orrick | 6 | US | CT | G | PVT | Erie | |
| George | Ort | 161 | OH | INF | D | PVT | Stark | |
| Jacob | A | Ort | 57 | OH | INF | B | PVT | Wood |
| John | G | Orth | 118 | OH | INF | G | PVT | Hancock |
| Louis | D | Orth | 2 | MI | INF | H | PVT | Erie |
| Frank | Orth | 37 | OH | INF | F | SGT | Ottawa | |
| James | S | Ortman | 6 | IA | INF | H | Franklin | |
| Bartholemew | Ortman | 95 | OH | INF | C | PVT | Franklin | |
| John | Ortman | 149 | OH | INF | D | CPL | Ross | |
| James | C | Orton | 3 | OH | CAV | C | PVT | Lucas |
| William | H | Ortt | 156 | OH | INF | D | 2LT | Preble |
| James | S | Orwig | 101 | OH | INF | K | PVT | Seneca |
| Samuel | G | Orwig | 183 | OH | INF | G | PVT | Wyandot |
| Patterson | Orwig | 57 | OH | INF | F | PVT | Hancock | |
| George | H | Osborn | 12 | OH | INF | I | PVT | Ross |
| Dwight | H | Osborn | 171 | OH | INF | K | PVT | Geauga |
| William | B | Osborn | 42 | OH | INF | H | MUS | Franklin |
| George | W | Osborn | 179 | OH | INF | E | PVT | Seneca |
| Seth | W | Osborn | 17 | OH | INF | G | PVT | Franklin |
| Jerome | Osborn | 164 | OH | INF | B | PVT | Seneca | |
| Ira | C | Osborn | 42 | OH | INF | A | CPL | Portage |
| Warner | Osborn | 144 | OH | INF | A | PVT | Seneca | |
| James | Osborn | 134 | PA | INF | E | CPL | Erie | |
| Ralph | Osborn | 26 | OH | INF | H | PVT | Franklin | |
| David | E | Osborn | 105 | OH | INF | E | PVT | Geauga |
| Jerome | Osborn | 55 | OH | INF | D | CPL | Huron | |
| Eugene | A | Osborn | 3 | OH | CAV | A | SGT | Huron |
| Williston | Osborn | 55 | OH | INF | C | PVT | Huron | |
| Emory | E | Osborn | 6 | OH | CAV | G | PVT | Stark |
| Joseph | E | Osborn | 55 | OH | INF | G | PVT | Sandusky |
| Isaac | Osborn | 77 | OH | INF | B | PVT | Delaware | |
| William | H | Osborn | 4 | OH | INF | H | PVT | Marion |
| Leroy | J | Osborn | 23 | OH | INF | H | PVT | Wood |
| William | E | Osborne | 32 | OH | INF | D | 1SGT | Paulding |
| Edward | Osgood | 40 | OH | INF | E | CPL | Darke | |
| Marquis | Osgood | 68 | OH | INF | D | PVT | Fulton | |
| Richard | H | Osgood | 5 | OH | CAV | A | 2LT | Franklin |
| Wentworth | A | Osgood | 85 | OH | INF | H | PVT | Franklin |
| Elijah | R | Osgood | 185 | OH | INF | C | PVT | Franklin |
| John | H | Osler | 26 | OH | INF | E | 1LT | Franklin |
| Henry | W | Osmond | 19 | OH | INF | F | PVT | Geauga |
| Herbert | D | Osmond | 177 | OH | INF | I | PVT | Geauga |
| Samuel | C | Oster | 91 | PA | INF | B | PVT | Ottawa |
| Derick | D | Osterholt | 123 | OH | INF | K | WAG | Seneca |
| John | Ostheimer | 189th | OH | INF | K | Montgomery | ||
| Walter | J | Ostrander | 111 | OH | INF | I | PVT | Wood |
| Jacob | Ostrander | 121 | OH | INF | C | PVT | Delaware | |
| Henry | Oswald | 111 | OH | INF | G | PVT | Sandusky | |
| Thomas | J | Oswald | 128 | PA | INF | I | PVT | Marion |
| Frank | Oswald | 14 | OH | INF | F | PVT | Henry | |
| Henry | Oswalt | 72 | OH | INF | G | PVT | Hamilton | |
| George | G | Oswalt | 102 | OH | INF | I | PVT | Wayne |
| Eli | Oswalt | 115 | OH | INF | B | PVT | Stark | |
| William | O | Oswalt | 115 | OH | INF | K | PVT | Stark |
| Jacob | H | Oswalt | 71 | OH | INF | F | PVT | Stark |
| John | Oswalt | 14 | OH | INF | G | PVT | Paulding | |
| David | N | Osyor | 9 | OH | CAV | F | SGT | Franklin |
| Valentine | Ott | 72 | OH | INF | A | PVT | Sandusky | |
| Joseph | Ott | 3 | OH | CAV | F&S | BUGL | Erie | |
| Adam | Ott | 184 | OH | INF | H | PVT | Portage | |
| George | Ott | 64 | OH | INF | K | PVT | Erie | |
| Benjamin | Franklin | Ott | 202 | PA | INF | G | PVT | Wyandot |
| Arron | Ott | 21 | PA | CAV | A | CPL | Wyandot | |
| John | F | Ott | 155 | OH | INF | F | PVT | Pickaway |
| Benjamin | Ott | 26 | OH | INF | B | PVT | Ross | |
| Samuel | C | Ott | 76 | OH | INF | I | PVT | Stark |
| Thomas | J | Ottarson | 74th | IN | INF | I | PVT | Montgomery |
| Heinrich | F | Otte | 11 | OH | INF | F | PVT | Henry |
| John | Otterbacher | 55 | OH | INF | B | PVT | Wood | |
| John | G | Ottgen | 111 | OH | INF | K | PVT | Fulton |
| Lewis | Otting | 9 | OH | INF | A | PVT | Erie | |
| Jacob | G | Ottinger | 68 | OH | INF | A | PVT | Fulton |
| Olivert | Ottley | 23 | OH | INF | G | PVT | Huron | |
| Anthony | Ottney | 72 | OH | INF | H | PVT | Sandusky | |
| Edward | T | Otto | 120 | OH | INF | C | PVT | Hancock |
| Ludwig | Otto | 72 | OH | INF | E | PVT | Ottawa | |
| Frank | Otto | 42 | OH | INF | C | SGT | Hancock | |
| Edwin | T | Otto | 144 | OH | INF | E | PVT | Hancock |
| J | O | Otto | 196 | OH | INF | K | PVT | Franklin |
| J | H | Otto | 120 | OH | INF | G | PVT | Stark |
| William | Otto | 148 | PA | INF | A | MUS | Wayne | |
| Israel | Otto | 148 | PA | INF | A | PVT | Wayne | |
| Nathan | J | Otto | 24 | IA | INF | B | PVT | Darke |
| John | H | Oty | 7 | OH | CAV | K | Franklin | |
| Lewis | A | Ours | 78 | OH | INF | H | PVT | Pickaway |
| James | Ousey | 2 | OH | ART | K | PVT | Delaware | |
| Hiram | OutCalt | 160 | OH | INF | A | PVT | Franklin | |
| Thomas | J | Outcalt | 17 | OH | INF | K | PVT | Franklin |
| Joseph | H | Outhwaite | 1 | OH | HART | L | PVT | Hancock |
| Alonzo | Outland | 192 | OH | INF | D | PVT | Paulding | |
| Joseph | H | Outwaite | 1 | OH | HART | L | PVT | Franklin |
| William | Ovendorf | 124 | OH | INF | B | Summit | ||
| Jacob | W | Over | 42 | OH | INF | C | PVT | Wayne |
| John | Over | 13 | OH | INF | B | PVT | Pickaway | |
| Daniel | Over | 77 | PA | INF | F | PVT | Sandusky | |
| E | L | Over | 42 | OH | INF | C | PVT | Wayne |
| John | Overbolt | 15 | PA | CAV | Wayne | |||
| Philip | Overcasher | 115 | OH | INF | E | WAG | Stark | |
| John | H | Overholser | 156 | OH | INF | D | CPL | Preble |
| David | F | Overholt | 133 | OH | INF | G | PVT | Hancock |
| Jacob | L | Overholt | 166 | OH | INF | E | Summit | |
| Lewis | Overholtz | 156 | OH | INF | E | PVT | Preble | |
| William | H | Overholtz | 35 | OH | INF | B | PVT | Preble |
| Richard | Overholtz | 93 | OH | INF | G | PVT | Preble | |
| Samuel | L | Overhulse | 134 | OH | INF | I | PVT | Henry |
| Jesse | A | Overhulse | 66 | OH | INF | G | PVT | Henry |
| Lewis | Overly | 18 | US | INF | G | Ross Co | ||
| Stephen | Overman | 20 | OH | INF | B | PVT | Preble | |
| George | B | Overmeyer | 186 | OH | INF | E | PVT | Sandusky |
| Homer | E | Overmeyer | 25 | OH | INF | E | CPL | Fulton |
| Issac | Overmeyer | 72 | OH | INF | B | PVT | Ottawa | |
| Samuel | B | Overmeyer | 72 | OH | INF | C | PVT | Sandusky |
| David | A | Overmier | 8 | OH | INF | F | PVT | Henry |
| Samuel | Overmier | 14 | OH | INF | D | PVT | Henry | |
| Amos | Overmyer | 169 | OH | INF | K | PVT | Sandusky | |
| Hiram | Overmyer | 68 | OH | INF | D | PVT | Paulding | |
| Albert | Overmyer | 57 | OH | INF | K | PVT | Sandusky | |
| Henry | H | Overmyer | 25 | OH | INF | E | CPL | Sandusky |
| George | W | Overmyer | 128 | OH | INF | I | PVT | Paulding |
| Isaiah | Overmyer | 169 | OH | INF | K | PVT | Sandusky | |
| Michael | Overmyer | 169 | OH | INF | K | PVT | Sandusky | |
| Michael | G | Overmyer | 72 | OH | INF | C | PVT | Sandusky |
| Noah | J | Overmyer | 110 | OH | INF | A | CPL | Franklin |
| Thomas | J | Overmyer | 25 | OH | INF | E | PVT | Sandusky |
| Aaron | Overmyer | 111 | OH | INF | A | PVT | Sandusky | |
| Franklin | Overpeck | 54 | OH | INF | E/H | PVT | Preble | |
| John | M | Overpeck | 34 | OH | INF | LT | Preble | |
| Henry | Overs | 120 | OH | INF | F | PVT | Wayne | |
| Lyman | Oviatt | 177 | OH | INF | E | PVT | Erie | |
| Emmon | S | Oviatt | 2 | OH | CAV | A | Summit | |
| Ed | Oviatt | 164 | OH | INF | F | Summit | ||
| Anderson | B | Oviatt | 19 | OH | INF | H | Summit | |
| Joseph | Frank | Owen | 33 | IL | INF | B | CPL | Lucas |
| Edward | M | Owen | 143 | IL | INF | H | PVT | Erie |
| William | Owen | 7 | KY | CAV | L | CPL | Erie | |
| John | Owen | 17 | OH | INF | C | PVT | Franklin | |
| Joseph | P | Owen | 67 | OH | INF | K | SGT | Erie |
| Silas | E | Owen | 6 | CA | INF | G | PVT | Huron |
| Robert | Owen | US | TMST | Portage | ||||
| Moses | M | Owen | 7 | OH | INF | F | PVT | Portage |
| Robert | T | Owen | 3 | OH | CAV | I | PVT | Erie |
| Arkison | B | Owen | 174 | OH | INF | I | MUS | Marion |
| John | W | Owen | 2 | OH | CAV | D | PVT | Stark |
| William | Owen | 49 | OH | INF | G | CPL | Seneca | |
| John | F | Owen | 164 | OH | INF | G | PVT | Seneca |
| Fredrick | Owen | 90 | OH | INF | A | PVT | Pickaway | |
| E | C | Owen | 18 | OH | INF | C | LT | Huron |
| Samuel | Owens | 22 | IN | LART | BATT | PVT | Darke | |
| William | Owens | 4 | OH | CAV | C | SGT | Hancock | |
| T | W | Owens | 193 | OH | INF | G | PVT | Darke |
| Allen | D | Owens | 166 | OH | INF | B | PVT | Huron |
| Thomas | Owens | 145 | OH | INF | A | PVT | Delaware | |
| George | C P | Owens | 112th | PA | INF | H | PVT | Montgomery |
| William | Owens | 2 | OH | INF | H | PVT | Franklin | |
| Henry | Owens | 65 | OH | INF | G | PVT | Stark | |
| Perry | Owens/Owings | 114 | OH | INF | A | PVT | Pickaway | |
| Frank | X | Owesney | 157 | OH | INF | A | PVT | Stark |
| Gale | Owings | 114 | OH | INF | A | Pickaway | ||
| James | Owry | 188 | OH | INF | I | PVT | Summit | |
| John | G | Oxer | 156 | OH | INF | H | PVT | Preble |
| Peter | Oxley | 141 | OH | INF | B | PVT | Athens | |
| Morris | M | Oxley | 146 | OH | INF | E | CPL | Erie |
| Eli | Oxley | 7 | OH | CAV | I | Athens | ||
| Jonas | Oyer | 61 | OH | INF | C | CPL | Franklin | |
| John | E | Oyer | 25 | OH | INF | D | WAG | Stark |
| Martin | M | Oyer | 115 | OH | INF | B | CPL | Portage |
| David | P | Oyer | 61 | OH | INF | C | PVT | Paulding |
| William | H | Oyer | 82 | OH | INF | D | PVT | Pickaway |
| John | E | Oyer | 162 | OH | INF | D | PVT | Paulding |
| Soloman | Oyster | 162 | OH | INF | D | PVT | Stark |