Area codes 812 and 930

Area codes 812 and 930 serve the southern third of the state of Indiana. The area codes cover Evansville and most of its suburbs, the northern suburbs of Louisville and the northwestern suburbs of Cincinnati. Other cities in the area code are Bedford, Bloomington, Columbus, Greensburg, Jasper, Princeton, Seymour, Terre Haute, and Vincennes.

The main area code, 812, was one of the original area codes introduced in 1947. Despite the presence of Evansville, Terre Haute and Bloomington, southern Indiana is not as densely populated as the rest of the state. As a result, this configuration remained in place for more than six decades, making 812 one of the few original area codes (not counting those covering an entire state) that still had its original boundaries.

On July 31, 2013, it was announced that 812 would be overlaid with area code 930, the state's first overlay. The move came because 812 was expected to exhaust in 2015; the supply of numbers was limited because portions of the Louisville and Cincinnati LATAs spill into the 812 territory, meaning numbers located in Louisville's 502, Cincinnati's 513 and northern Kentucky's 859 are not available for use. On March 1, 2014, a six-month permissive dialing period began, during which it was possible to complete calls within the 812 area with both seven and ten digits. Ten-digit dialing was originally planned to become mandatory in September 2014 with the first 930 numbers to become available in October. However, in August, the Indiana Utility Regulatory Commission delayed the implementation of mandatory ten-digit dialing until February 7, 2015, and the assignments of the first 930 numbers until March 7 to provide law enforcement and emergency medical services more time to update their telecommunication equipment. Until the implementation of 930, 812 had been one of the few original area codes (not counting single-state area codes) to have never been split or overlaid.

...
Wikipedia