Portland is a city located in the U.S. state of Oregon, near the confluence of the Willamette and Columbia rivers. As of the 2010 Census, it had a population of 583,776, estimated to have reached 587,865 in 2012 making it the 29th most populous city in the United States. Portland is Oregon's most populous city, and the third most populous city in the Pacific Northwest region, after Seattle, Washington and Vancouver, British Columbia. Approximately 2,260,000 people live in the Portland metropolitan area (MSA), the 23rd most populous MSA in the United States. Portland was incorporated in 1851 near the end of the Oregon Trail and is the county seat of Multnomah County.