Rumored Buzz on O'fallon Il Table of ContentsIndicators on O'fallon Hour You Need To KnowO'fallon Zip Code Fundamentals ExplainedNot known Details About O'fallon Our O'fallon Il IdeasO'Fallon is a city in St. Clair Region, Illinois, which was founded in 1854. O'Fallon's namesake originates from Colonel John O'Fallon, who was an affluent gent from