 US 30 continues east as an expressway , passing DeWitt to the south . Five miles ( 8 km ) east of DeWitt , it crosses back over to the north side of the Overland Route . West of the Clinton city limits is an interchange with Clinton County Road Z36 ( CR Z36 ) , which serves Low Moor and as a shortcut to southbound US 67 . East of CR Z36 , it passes the Clinton Municipal Airport and a large chemical plant . As it approaches Mill Creek Parkway , it descends over 100 feet ( 30 m ) in elevation into the flat Mississippi River valley , where it meets US 67 . 
