Beyond this junction, Route 34 expands into a four-lane divided highway, crossing over the Naugatuck River. It intersects Route 115 (for Ansonia and Seymour center) right after the bridge then turns southward as New Haven Avenue as it continues towards the town of Orange. In Orange, the road becomes Derby Turnpike and has intersections with Route 121 (for Milford) and Route 152 for Orange center. Along the way, it also has a cloverleaf junction with the Wilbur Cross Parkway (Exit 57-58). Route 34 soon enters the northern edge of West Haven, intersecting with Route 122 (for Westville and West Haven center. Soon after, the road downgrades to an undivided four lane road and crosses into New Haven where the road name changes to Derby Avenue. Route 34 then leaves Derby Avenue and joins Route 10 along Ella Grasso Boulevard for . East of Route 10, Route 34 is split into two one-way streets. Eastbound Route 34 turns onto Legion Avenue, later becoming South Frontage Road (former Oak Street), while westbound Route 34 uses North Frontage Road. The eastbound section running along Legion Avenue and South Frontage Road (1.03 miles) is town-maintained. The corresponding westbound section along North Frontage Road is officially designated as State Road 706 but is signed as Route 34 West.