Sarah Maria McKean Tacon was born 8 July 1777 in Newark, New Castle County, Delaware, United States to Thomas McKean (1734-1817) and Sarah Armitage (1756-1820) and died 4 January 1841 Spain of unspecified causes. She married Carlos Manuel Martínez de Irujo y Tacón Erice y Gámiz (1763-1824) 9 April 1798 in Philadelphia, Pennsylvania.
Sarah McKean was the daughter of US Founding Father Thomas McKean (1734-1817), one of the Signers of the US Declaration of Independence. Sarah married Spanish diplomat Carlos Martínez de Irujo, 1st Marquis of Casa Irujo; their son, Carlos Martínez de Irujo y McKean, would later become Prime Minister of Spain.
Children
| Name | Birth | Death | Joined with |
| Don Carlos Fernando De Yrujo (1799-) | |||
| Dona Marcisa Maria Louisa Martinez de Yrujo (1800-1874) | |||
| Carlos Fernando Martínez de Irujo y McKean Tacón y Armitage (1802-1855) | 14 December 1802 Washington, D.C., United States | 26 December 1855 Madrid, Spain | Lenouita Dona Gaberila d Aragon (1823-) |
Siblings
| Name | Birth | Death | Joined with |
| Joseph Borden McKean (1764-1826) | |||
| Robert McKean (1766-1802) | |||
| Elizabeth McKean (1767-1811) | |||
| Letitia McKean (1769-1845) | |||
| Mary McKean (1771-1781) | |||
| Anne McKean (1773-1804) | |||
| Name | Birth | Death | Joined with |
| Son McKean (1775-1775) | |||
| Sarah Maria Theresa McKean (1777-1841) | 8 July 1777 Newark, New Castle County, Delaware, United States | 4 January 1841 Spain | Carlos Manuel Martínez de Irujo y Tacón Erice y Gámiz (1763-1824) |
| Sophia Dorothea McKean (1779-1819) | |||
| Thomas Gerald McKean (1779-1852) | |||
| Maria Louisa McKean (1785-1788) | |||
| Child McKean (1787-) | |||
| Child McKean (1791-) | |||