Area code 636 - Wikipedia Area code 636 Missouri area code map Area code 636 serves east - central Missouri, mainly the metro area of St. Louis excluding the city of St. Louis and most of St. Louis County. Area code 636 includes parts of the community of Chesterfield, Fenton, and all of Washington, Union, De Soto, Troy, St. Charles, Jefferson, and Warren counties. Area code 314, now assigned to St. Louis and some suburbs, formerly extended to Washington and St. Francois counties. Before 1996, 314 covered the entire eastern half of Missouri. In 1996, most of the old 314 territory outside of the St. Louis area became area code 573. This was intended as a long - term solution, but within two years 314 was almost out of numbers again due to the proliferation of cell phones, pagers and fax machines. The supply of numbers was further limited because the St. Louis LATA spills into much of southern Illinois, meaning several numbers that were part of area code 618 across the border in Illinois were n't available. As a result, most of St. Louis ' outer - ring suburbs were switched to area code 636 on May 22, 1999. A permissive dialing period was allowed in which customers could still complete calls using 314. In popular culture In The Simpsons episode `` A Tale of Two Springfields '' which first aired on November 5, 2000, 636 is one of two area codes ( the other being 939 ) assigned to the fictional town of Springfield. See also NANPA Area Code Map of Missouri List of exchanges from AreaCodeDownload.com, 636 Area Code References Jump up ^ Swartzwelder, John ; Cashman, Shaun ( 2000 - 11 - 05 ). `` A Tale of Two Springfields ''. The Simpsons. Season 12. Episode 250. Fox. Missouri area codes : 314, 417, 573, 636, 660, 816 North : 573, 618, 314 West : 573 area code 636 East : 618, 314 South : 573, 314 Illinois area codes : 217, 224 / 847, 309, 312, 331 / 630, 618, 708, 773, 779 / 815, 872 Coordinates : 38 ° 36 ′ N 90 ° 36 ′ W ﻿ / ﻿ 38.60 ° N 90.60 ° W ﻿ / 38.60 ; - 90.60 This Missouri - related article is a stub. You can help Wikipedia by expanding it. This article related to a telephone area code is a stub. You can help Wikipedia by expanding it. Retrieved from `` https://en.wikipedia.org/w/index.php?title=Area_code_636&oldid=813068820 '' Categories : Area codes in the United States Area codes in Missouri Telecommunications - related introductions in 1999 Missouri stubs Area code stubs Talk About Wikipedia Add links This page was last edited on 1 December 2017, at 15 : 44 ( UTC ). Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: where is area code 636 located in usa
Answer: east-central Missouri, mainly the metro area of St. Louis excluding the city of St. Louis and most of St. Louis County