The largest city in the Pacific Northwest region of North America is Seattle.
The Pacific Northwest ( in the United States , commonly abbreviated as PNW ) , sometimes referred to as Cascadia , is a geographic region in western North America bounded by the Pacific Ocean to the west and ( loosely ) by the Rocky Mountains on the east . Seattle . With an estimated 704,352 residents , Seattle is the largest city in both the state of Washington and the Pacific Northwest region of North America .