East St. Louis School District #189 Mason-Clark Middle School School Public All Buildings Find Us 5510 State Street East St. Louis, IL 62203Get Directions Skip Filters Illinois Heartland Library System Resource Sharing ILDS Stop ZED Delivery Hub ZED OCLC Code L#J Other Information County St. Clair Branch Number 03 Building Enrollment 582 NCES Branch 171332004977 RCDTS Code 500821890221007