Mary was the daughter of Barzillai Delano of Duxbury, Plymouth County, Massachusetts and Elizabeth Delano of Duxbury, Plymouth County, Massachusetts. (Barzillai's parents were Amaziah Delano of Duxbury, Plymouth County, Massachusetts and Ruth S. Sampson of Duxbury, Plymouth County, Massachusetts. Elizabeth's parents were Lemuel Delano and Lydia Bartlett.) Elizabeth and Barzilla were married on 04 July 1779 in Duxbury, Plymouth County, Massachusetts. Elizabeth and Barzilla had eleven children. They were: Francis Delano was born on 05 August 1780; Amaziah Delano was born on 25 June 1782; Sophia Delano was born on 26 December 1783; Caleb Delano was born on 25 November 1785; Betsy Delano was born on 23 November 1787; Mary Delano was born on 10 April 1789; Hannah Delano was born on 11 May 1791; Julia Ann Delano was born on 11 December 1792; Sylvia Delano was born on 17 May 1796; Barzillai Delano was born on 01 May 1798; and Ruth Rogers Delano was born on 04 June 1800. All the children were born in Sidney, Kennebec County, Maine.

Mary married John Abbott on 01 November 1808 in Sidney, Kennebec County, Maine. Mary and John had seven children. They were: Joseph Lyman Abbott was born on 23 April 1812 in Dixfield, Oxford County, Maine; John Buckman Abbott was born on 02 November 1814 in Jay, Franklin County, Maine; William Flavil S. Abbott was born on 08 May 1817 in Jay, Franklin County, Maine; James Nason Abbott was born on 22 May 1825 in Sidney, Kennebec County, Maine; Henry Perry Abbott was born on 08 January 1828 in Sidney, Kennebec County, Maine; Edwin Croge Abbott was born on 09 November 1830 in Sidney, Kennebec County, Maine; and Charles Melvin Abbott was born on 17 February 1835 in Sidney, Kennebec County, Maine.