From 1954 to 1960, the British detained approximately 8000 women under the Emergency Powers imposed to combat the Mau Mau Rebellion in Kenya. Kamiti Detention Camp was the main site of women's incarceration, and its importance has been widely acknowledged by scholars. However, new documentary evidence released from the Hanslope Park Archive since 2011 has revealed the existence of a second camp established for women at Gitamayu, created in 1958 explicitly to deal with the remaining “hardcore” female detainees. This article examines the British struggle to contend with the hardcore Mau Mau women in the final years of the Emergency Period, one that was marked by uncertainty, violence, and an increasing reliance on ethno-psychiatry. Debates about how to deal with this group of women engaged and perplexed the highest levels of the colonial administration, generating tensions between legal, political, and medical officials. At the center of these debates was the question of the female detainees' sanity, with some officials pressing for these women to be classified as insane. The charge that hardcore women were “of unsound mind” was used for a variety of purposes in the late 1950s, including covering up the abuses in the camps. Examining the British approach to these detainees illuminates how ideas about gender, deviancy, and mental health shaped colonial practices of punishment.