The most populous cities in area code 636 are: Saint Charles, Chesterfield, O Fallon, Saint Louis, and Ballwin.
Other cities in the 636 area code include: Wentzville, Crystal City, Fenton, Saint Peters, Washington, Arnold, Valley Park, Imperial, Union, Earth City, High Ridge, Troy, Cedar Hill, Warrenton, Wildwood, Pacific, Portage Des Sioux, Maryland Heights, De Soto, Saint Ann, Eureka, Saint Clair, Herculaneum, Defiance, Gray Summit, Foristell, Hillsboro, Winfield, House Springs, Wright City, Marthasville, Moscow Mills, Augusta, Fletcher, Old Monroe, Foley, Jonesburg, Hawk Point, High Hill, Truxton, and New Haven.
St. Charles is a city in, and the county seat of, St. Charles County, Missouri, United States. The population was 65,794 at the 2010 census, making St. Charles the ninth-largest city in Missouri. It lies to the northwest, and is a suburb of St. Louis, Missouri on the Missouri River.Founded in about 1769 as Les Petites Côtes, or "The Little Hills" in French, by Louis Blanchette, a French-Canadian fur trader, when the area was nominally ruled by Spain following the Seven Years' War, it is the third-oldest city in Missouri. For a time, it played a significant role in the United States' westward expansion.It was settled primarily by French-speaking colonists from Canada in its early days and was considered the last "civilized" stop by the Lewis and Clark Expedition in 1804, which was exploring the western territory after the United States made the Louisiana Purchase. The city served as the first Missouri capital from 1821 to 1826, and is the site of the Saint Rose Philippine Duchesne shrine.
Chesterfield is a city in St. Louis County, Missouri, United States, and a Western suburb of St. Louis. As of the 2010 census, the population was 47,484, making it the state's fourteenth-largest city.The broader valley of Chesterfield was originally referred to as "Gumbo Flats", derived from its soil, which though very rich and silty, became like a gumbo when wet. Chesterfield is half the size of St. Louis.
O'Fallon / oʊ ˈ f æ l ən / is a city along Interstate 70 and Interstate 64 between Lake St. Louis and St. Peters in St. Charles County, Missouri. It is part of the St. Louis Metropolitan Statistical Area. As of the 2010 census O'Fallon had a population of 79,329, making it the largest municipality in St. Charles County and seventh largest in the state of Missouri. In 2006 Money Magazine named O'Fallon 39th in its "Best 100 Places to Live." Money Magazine also ranked O'Fallon 68th out of 100 in 2008 and 26th out of 100 in 2010. O'Fallon's namesake in St. Clair County, Illinois is also part of the St. Louis Metropolitan Statistical Area. The two O'Fallons are one of the few pairs of same-named municipalities to be part of the same MSA.
The 636 area code lies within the Central Daylight Time Zone (or CDT). The current time in Central Daylight Time is 10:44 AM on May 19, 2022.
