1850 Census Ward 1
O
| 1 | 157 | 177 | Susan | O'Brien | 26 | F | Virginia | ||
| 1 | 157 | 177 | John | O'Brien | 32 | M | Watchman | Ireland | |
| 1 | 157 | 177 | Mary V | O'Brien | 4 | F | Baltimore | ||
| 1 | 157 | 177 | Annabel | O'Brien | ### | F | Baltimore | ||
| 1 | 270 | 315 | Henry | O'Brien | 25 | M | Laborer | Baltimore | |
| 1 | 415 | 499 | Bridget | O'Brien | 17 | F | Ireland | ||
| 1 | 483 | 585 | Mary | O'Brien | 7 | F | Ireland | ||
| 1 | 1216 | 1650 | Bridget | O'Brien | 20 | F | Brass Founder | Ireland | occupation? |
| 1 | 1287 | 1745 | Michael | O'Brien | 28 | M | Butcher | Ireland | |
| 1 | 418 | 503 | John J | O'Connell | 14 | M | Baltimore | ||
| 1 | 418 | 503 | Sarah | O'Connell | 41 | F | Virginia | ||
| 1 | 418 | 503 | Thomas | O'Connell | 41 | M | Bootmaker | Ireland | |
| 1 | 418 | 503 | George W | O'Connell | 7 | M | Baltimore | ||
| 1 | 590 | 732 | James | O'Hanna | 24 | M | Laborer | Ireland | |
| 1 | 1010 | 1333 | Mary | O'Leary | 15 | F | Ireland | ||
| 1 | 236 | 284 | Thomas | O'Neil | 1 | M | Conn | ||
| 1 | 236 | 284 | Thomas | O'Neil | 22 | M | Ireland | ||
| 1 | 236 | 284 | Catharine | O'Neil | 30 | F | Ireland | ||
| 1 | 236 | 284 | John | O'Neil | 33 | M | Laborer | Ireland | |
| 1 | 236 | 284 | John | O'Neil | 4 | M | Ireland | ||
| 1 | 236 | 284 | Mary | O'Neil | 5 | F | Ireland | ||
| 1 | 236 | 284 | Michael | O'Neil | 9 | M | Ireland | ||
| 1 | 1068 | 1416 | Mary A | O'Neil | 1 | F | Ireland | ||
| 1 | 1068 | 1416 | Bridget | O'Neil | 26 | F | Ireland | ||
| 1 | 1204 | 1635 | Bridget | O'Neil | 24 | F | Ireland | check last name | |
| 1 | 1204 | 1635 | Mary | O'Neil | 4 | F | Ireland | ||
| 1 | 1204 | 1635 | James | O'Neil | 48 | M | Grocer | Ireland | Check last name |
| 1 | 1204 | 1635 | James | O'Neil | 7 | M | Ireland | ||
| 1 | 894 | 1168 | John | Oackf | 14 | M | Germany | ||
| 1 | 894 | 1168 | Jacob | Oackf | 36 | M | Laborer | Germany | |
| 1 | 894 | 1168 | Magdelia | Oackf | 36 | F | Germany | ||
| 1 | 894 | 1168 | George | Oackf | 4 | M | Maryland | ||
| 1 | 525 | 641 | Henry | Oast | 22 | M | Hanover, Germany | ||
| 1 | 10 | 12 | Matilda | Oastler | 1 | F | Baltimore, Md. | ||
| 1 | 10 | 12 | Barbara | Oastler | 28 | F | Baltimore, Md. | ||
| 1 | 10 | 12 | Thomas | Oastler | 3 | M | Baltimore, Md. | ||
| 1 | 10 | 12 | John | Oastler | 30 | M | Plumber | Baltimore, Md. | |
| 1 | 10 | 12 | Jane | Oastler | 8 | F | Baltimore, Md. | ||
| 1 | 10 | 12 | William | Oastler | 8 | M | Baltimore, Md. | ||
| 1 | 22 | 27 | Herman | Odeinan | 35 | M | Seaman | Biean, Germany | |
| 1 | 23 | 27 | Charles H | Odeinan | 10 | M | Baltimore, Md | ||
| 1 | 23 | 27 | John | Odeinan | 12 | M | Baltimore, Md | ||
| 1 | 23 | 27 | Daniel | Odeinan | 2 | M | Baltimore, Md | ||
| 1 | 23 | 27 | Catharine | Odeinan | 30 | F | Rhine, Germany | ||
| 1 | 23 | 27 | Georgeana | Odeinan | 6 | F | Baltimore, Md | ||
| 1 | 53 | 61 | Susan | Offend | |||||
| 1 | 936 | 1234 | Josephine | Ogden | 1 | F | Penna | ||
| 1 | 936 | 1234 | Daniel | Ogden | 27 | M | Mariner | Penna | |
| 1 | 1173 | 1592 | Henry | Ogle | 24 | M | Moulder | England | |
| 1 | 1173 | 1592 | Rachael | Ogle | 24 | F | Germany | ||
| 1 | 1173 | 1592 | Charles | Ogle | 7 | M | Maryland | ||
| 1 | 936 | 1234 | Mary E | Ognen | 20 | F | Penna | ||
| 1 | 153 | 173 | Sarah | Old | 20 | F | Somerset Co., Md | ||
| 1 | 153 | 173 | Richard | Old | 32 | M | Talbot Co., Md | ||
| 1 | 300 | 354 | Sarah | Old | 22 | F | Baltimore | ||
| 1 | 300 | 354 | Joseph H | Old | 27 | M | Pattern Maker | Baltimore | |
| 1 | 300 | 354 | Joseph | Old | 3 | M | Baltimore | ||
| 1 | 300 | 354 | Emma | Old | 4 | F | Baltimore | ||
| 1 | 566 | 697 | Ann | Oldner | 18 | F | Norfolk, Va | ||
| 1 | 279 | 324 | Mary | Olin | 86 | F | (blind) | Virginia | |
| 1 | 970 | 1280 | Jane | Olive | 32 | F | Maryland | ||
| 1 | 970 | 1280 | Thomas | Olive | 34 | M | Waterman | Virginia | |
| 1 | 154 | 174 | Ann R | Oliver | 2 | F | Baltimore | ||
| 1 | 154 | 174 | Ann | Oliver | 24 | F | Baltimore | ||
| 1 | 154 | 174 | Francis | Oliver | 32 | M | France | ||
| 1 | 154 | 174 | Lavenia | Oliver | 4 | F | Baltimore | ||
| 1 | 154 | 174 | Francis | Oliver | 6 | M | Baltimore | ||
| 1 | 1234 | 1672 | Bridget | Omelva | 14 | F | Ireland | ||
| 1 | 559 | 686 | Caroline | Openheimer | 41 | F | Biean, Germany | ||
| 1 | 559 | 686 | Hurtz | Openheimer | 41 | M | Tailor | Biean, Germany | |
| 1 | 559 | 686 | Barbara | Openheimer | 45 | F | Biean, Germany | ||
| 1 | 941 | 1240 | Ann | Orndoff | 228 | F | Germany | ||
| 1 | 941 | 1240 | Henry | Orndoff | 25 | M | Brickmaker | Germany | |
| 1 | 941 | 1240 | Sophia L | Orndoff | ### | F | Maryland | ||
| 1 | 941 | 1240 | Lewis | Orndoff | 5 | M | Germany | ||
| 1 | 1317 | 1795 | Simon | Orr | 35 | M | Mariner | Rhode Island | Peter Smith's Board. |
| 1 | 1196 | 1621 | Ann M | Orsendoff | 2 | F | Maryland | ||
| 1 | 1196 | 1621 | Eliza | Orsendoff | 2 | F | Maryland | ||
| 1 | 1196 | 1621 | Eliza | Orsendoff | 24 | F | Germany | ||
| 1 | 1196 | 1621 | Barney | Orsendoff | 26 | M | Laborer | Germany | |
| 1 | 37 | 45 | Susan | Osburn | 68 | F | Baltimore Co., Md | ||
| 1 | 504 | 755 | Wolf | Ospinger | 31 | M | Pedler | Biean, Germany | |
| 1 | 604 | 755 | Hannah | Ospinger | 31 | F | Biean, Germany | ||
| 1 | 604 | 755 | Leypold | Ospinger | 5 | M | Biean, Germany | ||
| 1 | 1319 | 1798 | Isaac | Osterday | 36 | M | Machinist | Germany | |
| 1 | 1319 | 1798 | Jane | Osterday | 40 | F | Germany | ||
| 1 | 1197 | 1623 | Mary A | Otten | 64 | F | Germany | ||
| 1 | 1197 | 1623 | Henry | Otten | 74 | M | Germany | ||
| 1 | 951 | 1254 | Henry | Otter | 13 | M | Germany | ||
| 1 | 951 | 1254 | Charles | Otter | 15 | M | Germany | ||
| 1 | 951 | 1254 | Henrietta | Otter | 41 | F | Germany | ||
| 1 | 1171 | 1590 | Caroline | Otter | 12 | F | Germany | ||
| 1 | 1196 | 1620 | Andrew | Otter | 36 | M | Laborer | Germany | |
| 1 | 1196 | 1620 | Catharine | Otter | 36 | F | Germany | ||
| 1 | 1196 | 1620 | Clemence | Otter | 5 | M | Maryland | ||
| 1 | 1196 | 1620 | Andrew | Otter | 9 | M | Germany | ||
| 1 | 868 | 1128 | Jane E | Owen | 45 | F | Maryland | ||
| 1 | 284 | 332 | Geroge | Owens | 60 | M | Sexton | Virginia | |
| 1 | 341 | 406 | Judith | Owens | 52 | F | Virginia | ||
| 1 | 428 | 514 | Mary A | Owens | 18 | F | Somerset Co., Md | ||
| 1 | 903 | 1182 | Mary V | Owens | 1 | F | Maryland | ||
| 1 | 903 | 1182 | Susan M | Owens | 10 | F | Marland | ||
| 1 | 903 | 1182 | James A | Owens | 12 | M | Maryland | ||
| 1 | 903 | 1182 | Mary M | Owens | 32 | F | Maryland | ||
| 1 | 903 | 1182 | Henry | Owens | 42 | M | Laborer | Maryland | |
| 1 | 903 | 1182 | Joseph E | Owens | 5 | M | Maryland | ||
| 1 | 1061 | 1407 | Robert | Owens | ### | M | Maryland | ||
| 1 | 1061 | 1407 | Thomas | Owens | 21 | M | Laborer | Maryland | |
| 1 | 1061 | 1407 | Susan | Owens | 27 | F | Maryland | ||
| 1 | 1061 | 1407 | Richard | Owens | 3 | M | Maryland | ||
| 1 | 1061 | 1407 | John | Owens | 30 | M | Storekeeper | Maryland | |
| 1 | 1061 | 1407 | Robert | Owens | 35 | M | Ferryman | Maryland | |