| Area Code | 636 |
| State | Missouri |
| Current Time in Area Code 636 | 636> CDT |
| Timezone | Central Daylight Time |
| Regional Market Area | Metro St. Louis |
| Population (2020) | 831789 |
| Adjacent Area Codes | 314,573,618,730 |
| Franklin County |
| Jefferson County |
| Lincoln County |
| Saint Charles County |
| Warren County |
| Ballwin |
| Chesterfield |
| O'Fallon |
| St. Charles |
| St. Peters |
| Wentzville |
| Wildwood |