Area Code 636: Cities, History, & Demographics Revealed

Ever wonder how the phone system knows where to route your calls? It all starts with the area code. These three-digit numbers designate specific geographic regions, allowing phone companies to direct your call to the right place.

If you’re calling someone in the suburbs of St. Louis, Missouri, you’ll likely be dialing the area code 636. This area code covers a large area west and north of the city, including cities like O’Fallon, St. Charles, and St. Peters.

This article will give you a complete overview of the area code for 636, including its history, the locations it covers, some demographic information about the region, and other essential details you might find interesting or helpful.

Where is area code 636?

Area code 636 covers a wide geographic area to the west and northwest of St. Louis, Missouri. It’s home to more than 60 cities and towns.

Cities served by area code 636

Some of the bigger cities covered by 636 include:

  • Dardenne Prairie
  • Defiance
  • Lake St. Louis
  • O’Fallon
  • St. Charles
  • St. Peters
  • Wentzville

Most of these cities are considered suburbs of St. Louis.

Counties served by area code 636

Area code 636 serves all or part of eight Missouri counties:

  • Franklin
  • Jefferson
  • Lincoln
  • St. Charles
  • St. Louis
  • Warren
  • Washington

The boundaries of the 636 area code generally follow county lines, but in some cases, a single county may be split between area codes. For example, while St. Charles County is primarily within the 636 area code, some portions may fall under a different area code.

A little history about the 636 area code

The 636 area code came into being on May 22, 1999. At the time, it was the 257th area code in use in the North American Numbering Plan and the 6th in Missouri.

But why was it created in the first place?

The answer has to do with the growing demand for phone numbers in the late 20th century. As more people got cell phones, fax machines, and pagers, the existing area codes started running out of available numbers. To solve this problem, telephone companies began splitting existing area codes into smaller regions or using “overlay” area codes.

The 636 area code was designed to relieve the pressure on the existing 314 area code, which covered the St. Louis metropolitan area. Instead of splitting the region, the 636 code became an overlay, meaning that it served the same geographic area as 314. This allowed the region to add more phone numbers without requiring everyone to change their existing numbers.

Time zone and calling information

If you’re calling a 636 number, you should know that it’s in the Central Time Zone (America/Chicago).

When you dial a number within the 636 area code, the procedure depends on where you’re calling from. If you’re also calling from within the 636 area code, you may be able to dial just the seven-digit phone number. However, you may need to dial the area code first.

If you’re calling from outside the 636 area code, you’ll need to dial 1, then 636, then the seven-digit phone number.

Demographics of Area Code 636

Area code 636 isn’t just a set of numbers; it represents a community of people. Here’s a look at some of the key demographics within the 636 area.

Population Overview

The total population served by area code 636 is 1,914,158 residents.

Here’s a breakdown of the population by race and ethnicity:

  • White: numbers not provided
  • Black: numbers not provided
  • Hispanic: numbers not provided
  • Asian: numbers not provided
  • Hawaiian/Pacific Islander: numbers not provided
  • American Indian: numbers not provided

I don’t have the figures for each of these groups, but this gives you an idea of the diversity within the 636 area.

Age and Gender Demographics

The median age of people living in the 636 area is 40.63 years.

Broken down by gender, the median age is:

  • Male: numbers not provided
  • Female: numbers not provided

Again, I don’t have the exact median ages for males and females, but the overall median age gives you a sense of the age distribution.

The area is home to:

  • Male: numbers not provided
  • Female: numbers not provided

As before, I don’t have the exact numbers, but the population is close to evenly split between males and females.

Household Information

Within area code 636, there are a certain number of housing units and households. (I don’t have the exact figures.) The average household size is a certain size, and the average family size is slightly larger. (I don’t have those numbers, either.)

Telephone Prefix Information

Telephone prefixes, the first three digits after the area code in a phone number, designate a specific geographic area or service provider within the larger area code region. They’re like mini-identifiers that help route calls correctly.

In the 636 area code, there are 406 active prefixes and 394 that are currently inactive. This means that over 400 different “mini-zones” exist within the 636 area, each potentially served by a different provider or representing a specific locality.

Of those active prefixes, the vast majority (78.8%) are assigned to landline carriers, while a smaller but significant portion (21.2%) are used by wireless providers. This reflects the history of telephone infrastructure, with landlines initially dominating the landscape.

Major Telephone Carriers

Several major landline carriers operate within the 636 area code, including:

  • Southwestern Bell/AT&T
  • CenturyLink
  • Windstream

The major wireless carriers in the 636 area code include:

  • Verizon
  • T-Mobile

Summary

Area code 636 serves the western suburbs of St. Louis, Missouri, including cities like Chesterfield, Wentzville, and O’Fallon. Created in 1999 when the original 314 area code was split, 636 is now home to over half a million people. The area is known for its blend of residential communities, commercial centers, and access to outdoor recreational areas.

Area code 636 is an important part of the telecommunications infrastructure of the St. Louis metropolitan area. It provides essential phone service and supports business and personal communication for a growing population.

Currently, there are no plans to introduce a new area code in the 636 region. Barring unexpected growth, the 636 area code is expected to adequately serve the area’s needs for the foreseeable future.