Durham (/ˈdʌrəm/) is a city in and the county seat of Durham County in the U.S. state of North Carolina. Small portions of the city limits extend into Orange County and Wake County. The U.S. Census Bureau estimated the city's population to be 274,291 as of July 1, 2018, making it the 4th-most populous city in North Carolina, and the 79th-most populous city in the United States. The city is located in the east-central part of the Piedmont region along the Eno River. Durham is the core of the four-county Durham-Chapel Hill Metropolitan Area, which has a population of 542,710 as of U.S. Census 2014 Population Estimates. The US Office of Management and Budget also includes Durham as a part of the Raleigh-Durham-Chapel Hill Combined Statistical Area, commonly known as the Research Triangle, which has a population of 2,037,430 as of U.S. Census 2014 Population Estimates.