Her chief interest was geography, under the direction of Frank Debenham, who had helped to establish the discipline at Cambridge.
During World War II, Mitchell wrote parts of the Naval Intelligence Division Geographical Handbooks, especially those that related to Greece.
[1] She returned to teaching at Cambridge following the war, helping to develop physical and historical geography study at the university.
[4] Suffering from poor health for most of her life,[2] she often taught classes in her rooms, when she was confined to bed.
Mitchell led excursions to East Anglia and Leicestershire in the 1960s, where she lectured on mediaeval church architecture.