Deroche is an unincorporated community at the foot of Nicomen Mountain in the Fraser Valley region of southwestern British Columbia. Encompassing the northeastern part of Nicomen Island, the infrastructure is centred on the northern shore of Nicomen Slough. The locality, on BC Highway 7, is by road about 29 kilometres (18 mi) west of Agassiz, 89 kilometres (55 mi) east of Vancouver, and 21 kilometres (13 mi) east of Mission.