Area code 712
Area code 712 is the telephone numbering plan code for the western fifth of Iowa, including cities such as Spencer, Le Mars, Sioux City, Council Bluffs, Red Oak, Sheldon, Storm Lake, Carroll, Sac City and Shenandoah.
Area code 712 was one of Iowa's original three area codes, 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 with a new area code. Despite the proliferation of cell phones and pagers, it is currently projected to stay that way until at least 2045.