MISSOURI · AREA CODE GUIDE
636 area code location: O'Fallon and Saint Charles, Missouri
- Local date and time
- Central Time
Map data: HSIP (2010) · NANPA · US Census Bureau, checked 26 September 2026. Boundaries are approximate.
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Download the 636 area code map
A printable area code 636 location map, with time zone and state. Use the PNG image in a document or slide; the SVG stays sharp at any size.
636 area code at a glance
- State
- Missouri
- Primary cities
- O'Fallon, Saint Charles, and Saint Peters
- Established
- Population
- Largest community: O'Fallon, 96,101 (2025)Not an area-code population.
- Prefixes in service
- 430 as of 13 October 2026
An area code does not show where a caller is now.
History
Country and calling code: United States (+1).
Parent code: 314.
New code planned: No, as of 22 September 2026.
Time zone
- Central Time
- Standard time UTC−06:00
- Daylight saving time UTC−05:00
Counties and cities covered
636 numbers are issued across 46 communities. These are telephone exchange areas, which follow the phone network rather than city limits, so a place can sit just outside the boundary of the town it is named for.
Counties of the communities we could place (the code may reach further): St. Charles County, Lincoln County, St. Louis County, Franklin County, Warren County, Jefferson County, and Montgomery County.
- O'Fallon
- Saint Charles
- Saint Peters
- Wentzville
- Chesterfield
- Manchester
- Washington
- Troy
- Union
- Eureka
- Warrenton
- Pacific
- Valley Park
- De Soto
- Wright City
- Saint Clair
- Moscow Mills
- Fenton
- Hillsboro
- Winfield
- Marthasville
- Foristell
- Jonesburg
- Hawk Point
- New Melle
21 more communities
- Portage des Sioux
- Old Monroe
- Augusta
- High Hill
- Foley
- Truxton
- Antonia
- Cedar Hill
- Dardenne
- Defiance
- Festus Crystal City
- Gray Summit
- Harvester
- Herculaneum-Pevely
- High Ridge
- Holstein
- Imperial
- Maxville
- Orchard Farm
- Pond
- Ware
Notable places in 636
| Place | Where | What it is |
|---|---|---|
| Mid America Adventure | 3.0 km from Eureka | Amusement park |
| Spirit of St. Louis Airport | 6.3 km from Chesterfield | Airport |
| World Wide Technology Soccer Park | 2.3 km from Fenton | Stadium |
| St. Charles County Smartt Airport | 5.8 km from Orchard Farm | Airport |
| Butterfly House, Missouri Botanical Garden | 3.2 km from Chesterfield | Zoo |
| Lindenwood University | 1.5 km from Saint Charles | University, 10,951 12-month enrollment (2023–24) |
| St. Charles Airport | 5.7 km from Orchard Farm | Airport |
| Hidden Valley Ski Area | 4.2 km from Eureka | Resort |
| Logan University | 4.5 km from Chesterfield | College, 2,128 12-month enrollment (2023–24) |
| Midwest University | 3.5 km from Wentzville | University |
Questions about 636
Where is the 636 area code?
636 is in Missouri. Its numbers are issued in O'Fallon, Saint Charles, Saint Peters, and 43 other communities.
What time zone is area code 636 in?
636 is in Central Time. Daylight saving time is observed.
What cities are in the 636 area code?
O'Fallon, Saint Charles, Saint Peters, Wentzville, and Chesterfield, and 41 other communities.
What state is area code 636 in?
Area code 636 is in Missouri.
What counties are covered by area code 636?
Area code 636 covers communities in St. Charles County, Lincoln County, St. Louis County, Franklin County, Warren County, Jefferson County, and Montgomery County.
Is 636 a toll-free area code?
No. 636 is a geographic area code. The toll-free codes are 800, 833, 844, 855, 866, 877, and 888.
Sources: NANPA area code listing, NANPA places by area code, NANPA central office code assignments, U.S. Census Bureau population estimates, OMB metropolitan area delineations. Checked .
Business phone numbers in area code 636, answered by an AI agent
A local number for O'Fallon, Saint Charles, and Saint Peters, Missouri, with an AI receptionist that takes caller details, answers the questions you give it, and books appointments. Numbers depend on what carriers have left.