RTC’s three-county planning area is located in the southwest part of Washington State. The Columbia River forms the southern boundary of the region as well as the western boundary of Clark County. To the south of the Columbia River is the state of Oregon. Clark County is largely urban in character with downtown Vancouver and downtown Portland (Oregon) separated by a distance of less than ten miles. Klickitat County and Skamania County are rural in character. Within the RTC region is Mount St. Helens and the foothills of Mount Adams.
Clark County is the fifth most populous in the state of Washington, and is also home to Vancouver, the state’s fourth largest city. Clark County’s other two most populous cities are Camas and Battle Ground. The county seat and largest city in Klickitat County is Goldendale. The county seat and largest city in Skamania County is Stevenson. In total, the three-county region covers 4,156 square miles with Clark County comprising the smallest land area of just 628 square miles.