Nicomen Island is an island in the Fraser Valley region of southwestern British Columbia. Nicomen Mountain in the Douglas Ranges lies to the north across Nicomen Slough. Chilliwack Mountain lies to the south across the Fraser River.[1] Adjacent to the northeast is Skumalasph Island.[2] Dewdney, which by road is about 11 kilometres (7 mi) east of Mission, extends onto the northwestern end of the island. Deroche, which by road is about 29 kilometres (18 mi) west of Agassiz extends onto the northeastern end.