Area Code 636 is located in MO.
Cities located in 636 area code are Maryland Heights, Fenton, Winfield, Manchester, Crystal City, Maxville, Saint Louis, Saint Charles, Washington, Cedar Hill, Imperial, Herculaneum, Valley Park, Augusta, Harvester, Union, Warrenton, Chesterfield, O Fallon, Marthasville, De Soto, St Peters, Portage Des Sioux, Foristell, High Ridge, Pacific, Gray Summit, Dardenne, Pond, Saint Louis, Troy, Saint Clair, House Springs, Wentzville, Hawk Point, Foley, Moscow Mills, Wright City, Earth City, Defiance, Ladue, Fletcher, Saint Peters, Hillsboro, Jonesburg, Eureka, Saint Ann, High Hill, Truxton, Creve Coeur, Old Monroe, Weldon Spring, New Haven, Antonia, Saint Louis.
Counties located in this area code are Saint Louis County, Lincoln County, Jefferson County, Saint Charles County, Franklin County, Warren County, Saint Louis City County, Montgomery County