Durham, North Carolina, is the core of the four-county Durham-Chapel Hill MSA, which has a population of 504,357 as of Census 2010. The US Office of Management and Budget also includes Chapel Hill as a part of the Raleigh-Durham-Cary Combined Statistical Area, which has a population of 1,749,525 as of Census 2010. Effective June 6, 2003, the Office of Management and Budget redefined the federal statistical areas and dismantled what had been for decades the Raleigh-Durham-Chapel Hill MSA, and split them into two separate MSAs, though the region functions as a single metropolitan area.