Welcome to O'Fallon, Missouri! Below are various websites to help you adjust to your new city! City of O'Fallon Links City of O'Fallon O'Fallon Police Department O'Fallon Parks Department Renaud Center O'Fallon Citizens First O'Fallon Business Map and Directory St. Charles County Links St. Charles County Website St. Charles County Police St. Charles Library District St. Charles County Tax Assessor Schools West High School West Middle School Rock Creek Elementary School