Route 177 went for a short, 0.24 miles (0.39 km) state-maintained portion of Bridge Street in Somerville.

In 1974, the Department of Transportation turned maintenance of this short highway over to the borough of Somerville for future use.

[1] Entering downtown Somerville, South Bridge Street continued northward into a large residential community.

Passing to the east and west of several residential homes, South Bridge Street continued into the downtown portion, crossing the current-day Raritan Valley Line tracks maintained by New Jersey Transit and served the Somerville train station.

[5] By 1930, Routes 206 and 31 was shifted off of Bridge Street, running along a partially completed bypass of Somerville.