Mary De la Beche "Minnie" Nicholl FES (née Dillwyn; 25 June 1839 – 30 October 1922) was a lepidopterist and mountaineer.

She was the daughter of Lewis Llewelyn Dillwyn and Elizabeth (née De la Beche).

and two younger sisters, Amy Dillwyn (b.1845) a novelist and industrialist, and Sarah, known as Essie (b.

Her biography, based on her notebooks and diaries, shows that she was never happier than when making extremely hazardous climbs or river crossings.

[8] A biography of Mary De la Beche Nicholl was published in 1979 titled: Grandmother Extraordinary.