Raleigh )is the capital city and the second largest city in the state of North Carolina as well as the seat of Wake County. Raleigh is known as the "City of Oaks" for its many oak trees. According to the U.S. Census Bureau, the city's 2010 population was 403,892, over an area of 142.8 square miles (369.85 km²), making Raleigh currently the 43rd largest city in the United States. It is also one of the fastest growing cities in the country. The city of Raleigh is named after Sir Walter Raleigh.Raleigh, Durham, and Chapel Hill make up the three historically primary cities of the Research Triangle metropolitan region. The regional nickname of "The Triangle" originated after the 1959 creation of the Research Triangle Park, primarily located in Durham County, four miles from Downtown Durham and encompassed on three sides by the city of Durham and roughly midway between the cities of Raleigh and Chapel Hill and the three major research universities of NC State University, Duke University, and UNC-Chapel Hill.In 2003, the previous Raleigh-Durham-Chapel Hill metropolitan statistical area (MSA) was re-defined by the U.S. Office of Management and Budget, resulting in the formation of the Raleigh-Cary, NC MSA and the Durham, NC MSA.The Research Triangle region encompasses the U.S. Census Bureau's Combined Statistical Area (CSA) of Raleigh-Durham-Cary in the central Piedmont region of North Carolina. As of July 1, 2009 the estimated population of the Raleigh-Durham-Cary CSA was 1,742,816, while the Raleigh-Cary Metropolitan Statistical Area (MSA) was estimated at 1,125,827, making it the nation's fastest growing metropolitan area.Most of Raleigh is located within Wake County, with a very small portion extending into Durham County. The towns of Cary, Morrisville, Garner, Clayton, Wake Forest, Apex, Holly Springs, Fuquay-Varina, Knightdale, Wendell, Zebulon, and Rolesville are some of Raleigh's primary nearby suburbs and satellite towns.