[11] The Craig River's watershed covers 737 km2 (285 sq mi),[6] and its mean annual discharge is 69.3 m3/s (2,450 cu ft/s).

In British Columbia the Craig Headwaters Protected Area provides a corridor about 5 km (3.1 mi) wide around the Craig River from the Alaskan border to the Jekill River confluence.

[21] After the Jekill confluence the Craig River turns north, flowing east of Seraphim Mountain.

[2][12][16] Many major, glaciated mountains over 1,500 m (4,900 ft) tall are found in the Craig River watershed and along its drainage divides.

[25][2][12][16] The Craig River's watershed supports low elevation coastal western hemlock forest ecosystems and areas providing ideal growing conditions for Sitka spruce, with trees reaching over 60 m (200 ft) in height.

[26][27] The coastal forest valley of the Craig River provides excellent grizzly bear habitat,[13] and also supports populations of mountain goat and moose,[26] as well as black bear, wolf, beaver, fisher, marten, wolverine, hoary marmot, and various species of rodents, bats, birds, and amphibians.