The only thing more southerly than the Douglas Ranges, other than floodplain, is the unnamed hill-country that is most of Districts of Mission and part of Maple Ridge, from the Alouette River east across the upland to Hatzic Prairie.

Timber from the Douglas Ranges supplied mills around Harrison Bay and along the Fraser's waterfront from there to Ruskin and Whonnock, British Columbia.

Douglas Ranges wood especially went to mills at Mission City, which was the capital of cedar shake production in the world for many years.

Nearby Eddy Match Co., between Mission and Hatzic, was one of the two largest matchstick-making plant in the world; its only rival was in Hull, Quebec.

The Douglas Ranges are subjected to torrential and ongoing rain, and its valleys are deep and narrow and dank throughout the year.