The Pacific Northwest, as the name indicates, lies in the extreme north-west of the United States on the Pacific slope, and its character as a physical and human unit is undoubted in both the scientific and popular senses, although the extent of the region from each point of view differs widely. The region finds varied definition. From the standpoint of regional planning the Pacific Northwest Commission defined it as including "not only the Columbia Basin, but Puget Sound in north-western Washington, and that part of the Missouri basin lying in eastern Montana, as well as the coastal areas fronting the Pacific in Oregon and Washington. All are inseparably linked economically and socially into one zone." This whole area, embracing the States of Washington, Oregon, Idaho and Montana, has an area of 392,000 square miles and a population of three and a half millions.
But, again, the whole, while recognized by its authorities as a good planning unit, is geographically diverse, as well as being very large, and has three major divisions -- the Pacific mountain and valley section, the Columbia Basin section (that is mainly agricultural), and Montana, characterized by wheat farming and live-stock ranching, with spots of irrigated agricultural land.
The coastal section is dominated by the metropolitan influence of Portland and Seattle and their neighbours, while eastern Montana looks towards the Twin Cities. There are also marked political differences, the coastal section voting Republican, the "Inland Empire", centred on Spokane, voting Democratic, while Montana varies in its allegiance between the two major parties and has third party leanings. There is, however, one social factor tending for regionality in the Pacific Northwest. This is the unusual homogeneity of the population of the region, which is primarily AngloSaxon, with a considerable Scandinavian population in the port cities and in regions favourable to the fishing industries.