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 by population, with 223,284 residents as of July 1, 2008. Durham County as of July 1, 2008 has 262,715 residents. 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). Durham is the core of the four-county Durham MSA, which has a population of 489,762 as of July 1, 2008. 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 1,578,527 as of July 1, 2008.