There are 2 Post Offices in O'Fallon, Illinois, serving a population of 29,095 people in an area of 15 square miles. There is 1 Post Office per 14,547 people, and 1 Post Office per 7 square miles.
In Illinois, O'Fallon is ranked 1,051st of 1547 cities in Post Offices per capita, and 1,051st of 1547 cities in Post Offices per square mile.
Find addresses, phone numbers, fax numbers, hours & services for O'Fallon Post Offices.
US Post Office 1501 West Highway 50 O'Fallon, IL Mailing Service, Postal Services
United States Postal Service 1111 South Lincoln Avenue O'Fallon, IL Mailing Service, Postal Services