Area code 636
Area code for east-central Missouri
title: "Area code 636" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["area-codes-in-the-united-states", "area-codes-in-missouri", "telecommunications-related-introductions-in-1999"] description: "Area code for east-central Missouri" topic_path: "engineering" source: "https://en.wikipedia.org/wiki/Area_code_636" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Area code for east-central Missouri ::
::figure[src="https://upload.wikimedia.org/wikipedia/commons/5/59/NANPA_Missouri_Area_Codes_2022.gif" caption="Area codes of Missouri"] ::
Area code 636 is a telephone area code in North American Numbering Plan (NANP) for the east-central part of the U.S. state of Missouri, comprising mainly the western suburbs of St. Louis. It includes parts of Chesterfield and Fenton in St. Louis County, and all of St. Charles, Jefferson, and Warren counties, all of Franklin County with the exception of Sullivan, as well as the towns of High Hill and Jonesburg in Montgomery County and the southern portion of Lincoln County. It was created in 1999 in an area code split from area code 314, which was one of the original North American area codes of 1947.
History
When the American Telephone and Telegraph Company (AT&T) created a universal North American telephone numbering plan for Operator Toll Dialing in 1947, Missouri was divided into two numbering plan areas (NPAs), which received the area codes 314 and 816. Area code 314 identified the eastern part of the state, from the northeast corner of the state at the Illinois border along a southwestern line near Columbia and Jefferson City to the center of the state, and continuing southeast into the east side of the West Plains area to the Arkansas state line. The largest city of the area code was St. Louis on the Mississippi river in the east.
By 1995, the telephone subscriber base experience substantial growth, threatening the exhaustion of the numbering pool.{{cite web |url=https://www.nationalnanpa.com/pdf/old_pl/IL%2095-08-015.pdf |title=NANP-Split of 314 (Missouri) Numbering Plan Area (NPA) |work=Bellcore Letter IL-95708-015 |date=1995-08-31 |access-date=2022-12-07
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.{{cite web |url=https://www.nationalnanpa.com/pdf/pl-nanp-165.pdf |title=Geographic Split of 314 (Missouri) Numbering Plan Area (NPA) |publisher=Lockheed Martin (NANPA) |date=1999-02-23 |access-date=2022-12-07
Service area
Major cities in the numbering plan area are:
- Arnold
- Ballwin
- Chesterfield
- Eureka
- Lake St. Louis
- Manchester
- O'Fallon
- St. Charles
- St. Peters
- Town and Country
- Union
- Warrenton
- Washington
- Wentzville
- Wildwood
References
| This= area code 636 | N= 573, 618, 314 | S= 573, 314 | E= 618, 314 | W= 573 | S1=IL
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