In the center of Unionville, Route 4 intersects Route 177 and it intersects the southern end of Route 167 on the east end of the village. After crossing the Farmington River once again, it intersects Route 10 in the center of town. The road then meets SR 508 which provides access to I-84 while Route 4 eastbound traffic continues through one of the state's few jughandles.
Route 4 intersects with other roads in Unionville, including Route 177 and Route 167, crossing the Farmington River again before connecting to Route 10. The road then connects to SR 508 for access to I-84 while continuing eastbound through a unique junction.