Area code 712 is the telephone area code in the North American Numbering Plan (NANP) for the most western part of Iowa, including the cities of Spencer, Le Mars, Sioux City, Council Bluffs, Red Oak, and others. It was one of the original three area codes for the state of Iowa established in 1947, and is the only one that still has its original boundaries. It is one of the few remaining original area codes that has never been split or overlaid. According to Intelius data, the 712 area code covers roughly 131,199 phone numbers, and Sioux City is the largest city within this area code with a population of about 86,001.