U.S. Federal Route 6 is a north-south highwy in Northwestern New Haven County. It runs from the Litchfield County Line, near Southbury, to the Fairfield County Line, near Sandy Hook. U.S. Rt. 6 passes through the following town in New Have County. Southbury U.S. Rt. 6 is multi-plexed in New Haven County. Connecticut State Route 67, near Southbury. Interstate 84, from near Southbury to the Fairfield/New Haven County Line.