Connecticut State Route 34 is a main highway across New Haven County. It runs from the New Haven/Fairfield County Line, near Monroe, to Interstate 91/95 at New Haven. CT St Rt 34 passes through the following towns in New Haven County. Seymour Derby Orange West Haven New Haven CT St Rt 34 is multi-plexed in New Haven County. Connecticut State Route 10, in New Haven. CT St Rt 34 intersects the following highways in New Haven County. Connecticut State Route 188, at Seymour.