It heads west for 0.2 miles (0.32 km) then turns north onto South Washington Street.

After crossing the Pequabuck River, it soon has a junction with Route 72, connecting with it via a partial interchange allowing access to and from points east.

In Farmington, the road becomes Plainville Avenue and continues north across the southwestern part of town, passing Tunxis Community College before intersecting with U.S. Route 6 about 0.6 miles (0.97 km) north of the town line.

Route 177 soon enters the Unionville section of Farmington, where the road becomes South Main Street.

The road ends 0.7 miles (1.1 km) later at an intersection with US 44 and US 202 near Bond Pond in Canton center.