 East of Mulberry Grove, I-70/US 40 cross to the north side of the east–west rail line and again closely parallel each other into Fayette County.I-70 passes along the northern edge of Vandalia, with access to the county seat of Fayette County provided by an interchange with US 40 on the west side and US 51 (Kennedy Boulevard) to the north.Just east of US 51, I-70 crosses the Kaskaskia River.