The road is currently 5.33 miles (8.58 km) long; however, it originally extended south to the New Jersey state line and north to Willow Grove Road (former NY 210) when it was assigned as part of the 1930 renumbering of state highways in New York.

After passing Maple Avenue in the Jewish village of Kaser, NY 306 becomes Monsey–Ladentown Road[citation needed] for the rest of its run.

NY 306 quickly leaves the small village and reenters the town of Ramapo.

[3] Roughly 1 mile (1.6 km) north of Kaser, NY 306 intersects County Route 74 (CR 74).

NY 306 continues north past CR 80, and enters the village of Wesley Hills.