NY 304 begins at the New Jersey–New York border in Pearl River. South of the border is Montvale in Bergen County, in which NY 304 continues as County Route 503 (CR 503). NY 304 quickly becomes a four-lane road intersecting CR 33 and CR 30 in Pearl River. CR 33 provides a link to the downtown business district of Pearl River via Central Avenue. After its intersection with CR 30, NY 304 becomes a limited-access highway. This highway runs for about , with interchanges with Crooked Hill Road (northbound only) and CR 33 (Middletown Road) in Pearl River and NY 59 in Nanuet. The latter exit indirectly connects NY 304 with the PIP and the New York State Thruway (Interstate 87 or I-87 and I-287).