The area code 636 is located in St. Charles, Missouri.
Area code 636 serves St. Charles, Missouri and much of the western St. Louis metro in Missouri. It covers fast-growing suburbs, business hubs, and neighborhoods along the Missouri River and the I‑70 and I‑64/US‑40 corridors. Established on May 22, 1999 as a split from 314, this area code anchors daily life and commerce in and around St. Charles, the state’s first capital. It follows Central Time and includes many residential communities, retail centers, parks, and historic sites.
You’ll find 636 phone numbers in major cities such as:
From Historic Main Street in St. Charles and the Katy Trail State Park to August A. Busch Conservation Area and the retail corridors of Chesterfield Valley, 636 ties together many of the region’s best-known landmarks. It does not include the City of St. Louis, which uses 314/557, but it covers many nearby suburbs on the Missouri side of the metro area. If you see a 636 phone number, it’s typically from western St. Louis suburbs like St. Charles, O’Fallon, or Chesterfield. The area code sits entirely within Missouri and participates in the North American Numbering Plan.
“Area code 636 was created in 1999 as a split from 314.” (North American Numbering Plan Administrator)
An interesting note: St. Charles served as Missouri’s first state capital from 1821 to 1826, and today the county remains a major growth center in the state. U.S. Census Bureau data show that St. Charles County grew from 360,485 residents in 2010 to 405,262 in 2020 (U.S. Census Bureau). This growth helps explain why area code 636 remains a key identifier for new homes, businesses, and services across the western St. Louis metro.