Durham is a city in the U.S. state of North Carolina. It is the county seat of Durham County, though portions also extend into Wake County in the east and Orange County in the west. It is the fourth-largest city in the state, and the 85th-largest in the United States by population, with 233,252 residents as of the 2011 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).Durham is the core of the four-county Durham-Chapel Hill Metropolitan Area. which has a population of 534,578 as of U.S. Census 2013 Population Estimates.