La Salle County Highway 4 is a east-west highway that parellels I-80 on Marseilles Road. This provided a surface road alternative to I-80 and U.S. Rt. 6 between Ottawa and Morris, via IL St Rt 71, Grundy County Highway 26, and U.S. Rt. 6. LSCH 4 does not pass through any towns in La Salle County. LSCH 4 intersects the following major local roads in La Salle County. Illinois State Route 71 north of Ottawa. La Salle County Highway 15 north of Marseilles. La Salle County Highway 25 north of Seneca.