Cultus Lake is a lake, associated community and provincial park in the Fraser Valley region of British Columbia, Canada. It is the source of the Sweltzer River. Cultus Lake is located 11 kilometres (6.8 mi) south of the Chilliwack River, near the city of Chilliwack and approximately 80 kilometres (50 mi) east of Vancouver. In 1950, Cultus Lake became a provincial park of British Columbia. Cultus Lake covers an area of 656 hectares, evenly on either side of the lake. At one time the lake had a sawmill and booming ground until it became a provincial park in the 1950s.