Area codes 816 and 975

By late 1996, the proliferation of cell phones and market reforms related to deregulation by the Telecommunications Act of 1996 required an additional area code for northern Missouri.

On April 10, 1997, Southwestern Bell declared a Jeopardy Situation with the Missouri Public Service Commission (MPSC), which oversees telecommunications in the state, and the North American Numbering Plan Administration (NANPA).

[3] The rate centers of Lexington (259) and Warrensburg (429) moved to 660, despite being generally considered a part of the Kansas City area.

On June 4, 1997, the MPSC announced the split for October 12, 1997, when a permissive dialing period would commenced, until April 19, 1998, during which long-distance calls to the 660 territory could be completed using either 816 or 660.

On February 20, 2001, the overlay was approved by the North American Numbering Plan Administration (NANPA),[4] by assigning area code 975 for service starting October 20, 2001, which was later postponed to May 5, 2002.