For the listing of car, truck, and motorcycle dealerships, service centers, parts dealers, or body shops, located in O''Fallon.

For sites of businesses and organizations in O''Fallon related to computers and the Internet. This includes sites for and about businesses that sell/rent computer hardware and software, computer training, web design, Internet access, and support services.

For businesses in O''Fallon related to constructing, maintaining, and demolishing buildings and other structures, including heavy construction and civil engineering (e.g. such as roads, power plants, and pipelines). Architects, janitorial/housekeeping services, handyman services, and site preparation services are also included.