Greensboro is a commercial, manufacturing, and distribution center for the surrounding agricultural area and a headquarters for the insurance industry. The main economic activity is the production of cotton textiles. Other manufactures include microchips, chemicals and pharmaceuticals, electrical machinery, tobacco products, and building materials. Greensboro covers a land area of 105 sq mi, with a mean elevation of 837 ft. A 2006 real estate survey has estimated the population of Greensboro, North Carolina at 236,865.