Portland is the largest city in the U.S. state of Oregon and the seat of Multnomah County, located near the confluence of the Willamette and Columbia rivers. According to the 2010 Census, it had a population of 583,776. Portland is located in the Willamette Valley region of the Pacific Northwest, between the Pacific Ocean and the Cascade Mountains, and its climate is marked by warm, dry summers as well as damp, cool-to-chilly winter days. This climate is ideal for growing roses. Portland is located 70 miles east of the Pacific Ocean at the northern end of Oregon's most populated region, the Willamette Valley. Downtown Portland straddles the banks of the Willamette River which flows north through the city center and consequently separates the east and west portions of the city. Less than 10 miles from downtown the Willamette River flows into the Columbia River, the fourth-largest river in the United States, which divides Oregon from Washington State. Portland experiences a temperate climate with both oceanic and Mediterranean features. This climate is typified by warm, dry summers and cool, damp winters. Portland experiences a much more temperate climate than one would expect of its latitude, with snowfall and freezing temperatures happening infrequently. Portland's location is beneficial for several industries. Relatively low energy cost, accessible resources, north–south and east–west Interstates, international air terminals, large marine shipping facilities, and both west coast intercontinental railroads are all economic advantages.