Portland is a city located near the confluence of the Willamette and Columbia rivers in the U.S. state of Oregon. With a population of 583,776 (as of the 2010 census), it is Oregon's most populous city, and the third most populous city in the Pacific Northwest, after Seattle, and Vancouver. Approximately 2.3 million people live in the Portland metropolitan area (MSA), the 19th most populous in the United States as of July 2012. Portland was incorporated in 1851 and is the seat of Multnomah County. The city extends slightly into Washington County to the west and Clackamas County to the south. It is governed by a commission-based government headed by a mayor and four other commissioners. Portland's first mayor was Hugh O'Bryant, who served for one year. The city and region are noted for strong land-use planning and investment in public transit, supported by Metro, a distinctive regional-government scheme. Portland lies in the Marine West Coast climate region, which is marked by warm summers and rainy but temperate winters. This climate is ideal for growing roses, and for more than a century Portland has been known as "The City of Roses," with many rose gardens – most prominently the International Rose Test Garden. Portland is also known for its large number of microbreweries, and as the home of the Trail Blazers NBA basketball team.