Durham is a city in the U.S. state of North Carolina. It is the county seat of Durham County and also extends into Wake County. It is the fifth-largest city in the state, and the 85th-largest in the United States by population, with 228,330 residents as of the 2010 United States census. It is the home of Duke University and North Carolina Central University, and is also one of the vertices of the Research Triangle area (home of the Research Triangle Park).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.Durham is the core of the four-county Durham MSA, which has a population of 501,228 as of July 1, 2009. The US Office of Management and Budget also includes Durham as a part of the Raleigh-Durham-Cary Combined Statistical Area, which has a population of 1,742,816 as of July 1, 2009.