Area Code 636 History:
Area code 636 was put into service. Area code 636 was created from a split of area code 314.
Counties in Missouri within area code 636 include:
Franklin County, Jefferson County, Lincoln County, Montgomery County, Saint Charles County, Saint Francois County, Saint Louis County, and Warren County.
Major cities or places in Missouri within area code 636 include:
Area code 636 serves east-central Missouri including the larger cities and communities of Arnold, Ballwin, Chesterfield, Manchester, O'Fallon, St. Charles, St. Peters and Wildwood, in addition to many smaller communities within the area code 636 service area.