Area codes 314 and 557

Although area code splits were intended as long-term solutions, within only two years, 314 was close to exhaustion once again due to the proliferation of cell phones, fax machines and pagers in St. Louis.

As a result, 314 was reduced to include only the exchanges of Chestnut, Jefferson, Prospect, Flanders, Forest, Mission, Melrose, Webster Groves, Parkview, Evergreen, Riverview, Ferguson, Overland, Ladue, Kirkwood, Sappington, Mehlville, Oakville, Creve Coeur, Bridgeton, Hazelwood, Florissant, and Spanish Lake in the core of the St. Louis area.

[3] All other exchanges were reassigned to the new area code 636, effective May 22, 1999, with the permissive dialing period ending on February 26, 2000.

On October 24, 2000, the Missouri Public Service Commission announced plans to add a second area code for the 314 numbering plan area, creating an overlay, but postponed the implementation date (May 5, 2002) indefinitely on September 25, 2001, when the commission determined no immediate need for additional central office prefixes.

[5] More than twenty years after that announcement, area code 557 was overlaid on August 12, 2022, as the available numbers in 314 neared exhaustion.