Raleigh - Durham - Chapel Hill MSA --COUNTIES-- Chatham County Durham County Franklin County Johnston County Orange County Wake County --DEFINITION-- Metropolitan Statistical Area (MSA) A city of over 50,000 inhabitants together with the county in which it is located and contiguous counties which are economically and socially integrated with the central city. It may also consist of an urbanized area of 50,000 with a total metropolitan area population of at least 100,000. The Raleigh-Durham-Chapel Hill MSA consists of Chatham, Durham, Franklin, Johnston, Orange, and Wake Counties.