Mitchell was born as Agatha Wright in Buckingham County, Virginia, officially on 26 March 1887 – she claimed 13 March. She was the eldest of six children born to Archer “Archie” Wright. During her youth, she lived in the Oak Hill community, becoming a devoted member of its Baptist church.
Mitchell had four sisters and one brother; she would assist in looking after them as well as helping with household chores. She married George Mitchell, who couldn’t pronounce her name so instead called her Martha. The couple had two daughters, Annie and Dorothy. She worked as a housekeeper for several families.
Mitchell smoked a cigarette once, later claiming it made her sick, hence she never smoked again. She also never drank alcohol.
At the time of her 113th birthday, Mitchell had 12 grandchildren, 33 great-grandchildren, and 31 great-great-grandchildren. She lived with her younger daughter Dorothy, as she had outlived her elder daughter Annie. Her favourite dessert was reported to be cherry cobbler. All five of Mitchell’s siblings were still living as of 2000.
Mitchell died on 26 February 2001 at the age of 113 years, 336 days. She was the third-oldest person in the United States after Mary Anna Boone and Maud Farris-Luse.