| Name | Birth date | Relationship with Sean Mulcahey |
| Blais, Marie-Anne | Abt. 1775 | 5th great-grandmother |
| Blais, Mathew | Abt. 1685 | 8th great-grandfather |
| Blais, Pierre | Abt. 1715 | 7th great-grandfather |
| Blanche | | Wife of the great-granduncle |
| Blanchet, Gen. | Abt. 1720 | 7th great-grandmother |
| Blanchet, Jean | Abt. 1690 | 8th great-grandfather |
| Blanchet, Pierre | Abt. 1660 | 9th great-grandfather |
| Bleau, Dennis | | 2nd cousin once removed |
| | | 8th cousin once removed |
| | | 9th cousin |
| | | 8th cousin twice removed |
| | | 9th cousin once removed |
| Bleau, Paul | November 23, 1921 | Husband of the 1st cousin twice removed |
| | | Husband of the 7th cousin twice removed |
| | | Husband of the 8th cousin once removed |
| | | Husband of the 7th cousin 3 times removed |
| | | Husband of the 8th cousin twice removed |
| Bleau, Roger | | 2nd cousin once removed |
| | | 8th cousin once removed |
| | | 9th cousin |
| | | 8th cousin twice removed |
| | | 9th cousin once removed |
| Bleau, Susan | | 2nd cousin once removed |
| | | 8th cousin once removed |
| | | 9th cousin |
| | | 8th cousin twice removed |
| | | 9th cousin once removed |
| Blessington, Bridget | Abt. 1867 | Wife of the 2nd great-grandfather |
| Blouin, Catherine | Abt. 1660 | 9th great-grandmother |
| Boneau, Marie-Françoise | Abt. 1780 | 5th great-grandmother |
| Bonneau, Aug. | Abt. 1690 | 8th great-grandfather |
| Bonneau, Joseph | Abt. 1660 | 9th great-grandfather |
| Bonneau, Pierre | Abt. 1720 | 7th great-grandfather |
| Bonneau, Pierre | Abt. 1745 | 6th great-grandfather |
| Bonnedeau, Elisabeth | | 8th great-grandmother |
| Bonnedeau, Louis | | 9th great-grandfather |
| Bornemaun, Wilhemine | 1877 | 2nd great-grandmother |
| Bouchard, Louise | | 9th great-grandmother |
| Bourdon, Jacques | | 9th great-grandfather |
| Bourdon, Mar. | | 8th great-grandmother |
| Brennan, Della | 1882 | 2nd great-grandaunt |
| Brennan, Edith M. | 1878 | 2nd great-grandmother |
| Brennan, Mabel | 1879 | 2nd great-grandaunt |
| Brennan, Michael | Abt. 1855 | 3rd great-grandfather |
| Brennan, Muriel | June 29, 1887 | 2nd great-grandaunt |
| Briau, Marie | | 9th great-grandmother |
| Brière, Anne | | 8th great-grandmother |
| Brière, Jean | | 9th great-grandfather |
| Brisson, Marie-Gen. | | 8th great-grandmother |
| Brisson, René | | 9th great-grandfather |