Douglas Channel is one of the principal inlets of the British Columbia Coast. Its official length from the head of Kitimat Arm, where the aluminum smelter town of Kitimat to Wright Sound, on the Inside Passage ferry route, is 90 km (56 mi). The actual length of the fjord's waterway includes waters between there and the open waters of the Hecate Strait outside the coastal archipelago, comprising another 60 km (37 mi) for 140 km (87 mi) in total.
A major side-inlet, the Gardner Canal, is 90 km (56 mi) in length, and is accessed from the Kitimat Arm of Douglas Channel via Devastation Sound (20 km, 12 mi), which is on the east side of Hawkesbury Island. South of Hawkesbury is Varney Passage (40 km, 25 mi), which has a sidechannel, Ursula Passage (30 km, 19 mi). Total waterway length of the fjord dominated by Douglas Channel is therefore, not counting smaller side-inlets, 320 km (200 mi), longer than Norway's Sognefjord (203 km, 126 mi) and rivalling Greenland's Scoresby Sund at 350 km (217 mi), though not as long as nearby Dean Channel's total of 335 km (208 mi).
Douglas Channel is a busy shipping artery because of the methanol import terminal (formerly methanol production and export) and the aluminum smelter at Kitimat, as bauxite must be shipped in and smelted aluminum shipped out. Recently announced (2005) plans will see a major expansion of the port of Kitimat as a container and bulk resources port, augmenting the port capacity of the British Columbia's North Coast currently a monopoly of the city of nearby Prince Rupert.
The methanol production and export plant closed in 2006.
Douglas Channel will be subject due to new sensitive ship traffic when the LNG Canada natural gas storage and liquefaction terminal will be completed and operational, which is estimated to be in 2025. The LNG Canada project, led by an LNG subsidiary of Royal Dutch Shell and several Asian partners and finally approved on October 1, 2018, will see large LNG carrier ships loading liquefied natural gas at the future Kitimat LNG terminal, to carry it to export destinations, mainly in Asia.
The Gardner Canal is important for being the location of the Kemano generating station of the Nechako Diversion, which was built to supply power for Kitimat. The head of the Gardner Canal, also, is the mouth of the Kitlope River, a major wildlife and wilderness preserve and area of outstanding natural beauty (and harsh weather).