The Appalachian subregions are contiguous regions of relatively homogeneous characteristics (topography, demographics, and economics) within Appalachia. This classification was developed in the early history of the ARC and provides a basis for subregional analysis. ARC revised the classification in November 2009 by dividing the Region into smaller parts for greater analytical detail and by using current economic and transportation data. Public Law 117-58, signed on November 15, 2021, added three counties (Catawba and Cleveland in North Carolina and Union in South Carolina) to the ARC program and altered the definition of North Central Appalachia by including the West Virginia counties of Brooke, Hancock, Marshall, and Ohio. For a list of county data by state, see the downloadable Excel file below.