The Pacific Northwest & The
Columbia River Basin
The Pacific Northwest can be briefly
described as the region drained by the Columbia/Snake River system. There is no
universal agreement about how far beyond that core area the term is
appropriate. Political divisions pull the definition one way, physical geography
another.
The Columbia rises in Canada, and so
does the Fraser, whose delta occupies the northern end of Washington’s Puget
Sound country. The two rivers follow the same notable pattern, flowing
northwest along the Rocky Mountain Trench before swinging abruptly south. (The
trench continues unbroken from Idaho to Alaska, the expression of long-term
tectonic shifts affecting the entire region).
This map extends up to the
headwaters of the Columbia above Banff, east to the Continental Divide, south
into northern Nevada for the southern tributaries of the Snake, and into
California for the southernmost Cascades.
Included on the map: All of
Washington, Oregon, Idaho, as well as a small portion of northern California,
with lots of British Columbia, Alberta, and Montana.
Small - Scale is 1:2 million or 1" = about 32 miles
Large - Scale is 1:1.5 million or 1" = about 24 miles
Dimensions: All map dimensions are approximate 
