Durham is an important industrial, educational, technology and health care center. The seat of Durham County, it is located about 20 miles (32 km) northwest of Raleigh in the north central part of the state. With Raleigh and Chapel Hill it forms a metropolitan area of more than 1,500,000 people. The Durham area was first settled by Scotch Irish in the 1750's. It began to grow after the coming of the railroad and industrial development shortly before the Civil War. The chief industry was tobacco, developed in large part by the Duke family, founders of American Tobacco Company. Duke philanthropy developed Duke University and the Duke University Medical Center , two of the mainstays of the local economy. Also of critical economic importance is the 5000-acre Research Triangle Park, founded in 1959 as an industrial and governmental research center.