Geography overview:

Washington State is one of the world's great travel destinations and offers an incredible diversity of geography which provide great flying opportunities. The state is home to nearly seven million people. Western Washington features lush forests and a cooler/wetter climate. It is home to most of the state's population including the cities of Seattle, Everett, Tacoma and Olympia. Eastern Washington is much warmer/drier and features a high-desert climate. Much of this region is devoted to agriculture. The Olympic Mountains in northwest Washington are rugged peaks and the home of Olympic National Park. The Cascade Mountains are a system of volcanic peaks and feature Mount Baker, Mount Adams, Mount Rainier (Washington's highest peak), and Mount St. Helens, which is an active volcano. All of these areas offer beautiful flying in X-Plane!

Special bonus:

The Washington RealScenery package also includes the northern Oregon Cascade Mountains and Mt. Hood, Oregon's highest peak. Commercial air traffic flying into Portland, Oregon pass very close to Mt. Hood. Also included is the Portland, Oregon metropolitan area which includes these major airports:
Portland International (KPDX)
Porland-Troutdale (KTTD)
Portland-Hillsboro (KHIO)

Major airports in Washington:

Seattle-Tacoma International (KSEA)
Paine Field (KPAE)
Boeing Field / King County International (KBFI)
McChord Air Force Base (KTCM)
Renton Municipal (KRNT)
Spokane International (KGEG)
Fairchild Air Force Base (KSKA)
Yakima Air Terminal (KYKM)
Tri-Cities Airport (KPSC)
Olympia Regional Airport (KOLM)

Boeing commercial aircraft are manufactured at KPAE, KBFI, and KRNT.