The southern terminus is at an intersection with U.S. Route 9 northbound in Beachwood, where it heads northward along Atlantic City Boulevard.

[2] After landing down on the Toms River side, Route 166 heads to the northwest, intersecting with the incomplete Herficker Boulevard.

The highway continues northward along commercial buildings as Main Street, passing to the west of Toms River High School South and back into the residential districts.

At the intersection, Route 166 switches names from Main Street to Lakewood Road, which heads northwestward.

A short distance later, the highway begins a split parallel with the Garden State Parkway and U.S. Route 9 to the east.

Route 166 then leaves the commercial and industrial districts for the residential ones soon later, crossing through several developments including Colonial Gardens.

After an intersection with Briar Knoll, Route 166 divides, approaching Interchange 83 on the Garden State Parkway, where the designation terminates.