Alice Walker, from Derbyshire, scored a perfect 14 out of 14 in her specialist subject, the Peak District.
Ms Walker - who won by six points in the grand final - was cheered on by a performance from the Morris dancing troupe she belongs to during the show, which aired on BBC Two on Monday.
The now 67-year-old said it was a "shock" to win.
"I applied for Mastermind after watching the programme and thought about entering for many years, but never expected to win, and it was quite a shock when I did," the retired IT consultant said.
"The opposition in the final was very tough but the questions just seemed to fall my way. It was a great experience and such an honour to receive the beautiful trophy."
The previous oldest female winner was Isabelle Heward, who took the title at her fourth attempt at the age of 61 in 2017.
Ms Walker's win follows 2021 champion Jonathan Gibson, a PhD student from Glasgow, who became the youngest person to win the show last year aged 24.
She has been part of the Macclesfield and Stockport quiz league since the 1980s, the show's producers said, and entered this year's Mastermind after contemplating applying for years.
"I'm not getting any younger. It's time," she said.
Retrieved from：https://www.bbc.com/news/uk-england-derbyshire-61070018 (8 April, 2022)
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