Illinois State Route 146 is a east-west highway across Central Johnson County. This is the main highway across Johnson County. IL St Rt 146 passes through the following towns in Johnson County. West Vienna Vienna Grantsburg IL St Rt 146 is no tmulti-plexed in Johnson County. IL St Rt 146 intersects the following highways in Johnson County. Illinois State Route 37, near West Vienna. U.S. Rt. 45, at Vienna.