 Major cities in the coverage area include Jonesboro, Mountain Home, Pine Bluff, Texarkana, El Dorado, and West Memphis.The area code was the first to split from Arkansas's original area code, 501.The supply of unassigned phone numbers for 870 was projected to run out sometime in 2013, according to the Arkansas Public Service Commission, prompting a December 2009 approval of a plan for an eventual overlay area code in this portion of the state.