The Piedmont Atlantic Megaregion (PAM) is a neologism created by the Regional Plan Association for an area of the Southeastern United States that includes the Atlanta, Birmingham, Charlotte, Memphis, Nashville, Research Triangle (Raleigh-Durham), and Greensboro-Winston-Salem-High Point metropolitan areas. The megaregion generally follows the Interstate 85/20 corridor. According to Georgia Tech, PAM represents over 12 percent of the total United States population and covers over 243,000 square miles (630,000 km2) of land.