- Southern Terminus:
- Chestnut Ridge Road (Bergen CR 73) at the New York-New Jersey state line
- Northern Terminus:
- US 202 in Mount Ivy
- 8.57 miles
NY 45 is a north/south route in Rockland County. Chestnut Ridge Road exists as a county road in Montvale, New Jersey, where it is designated Bergen CR 73. At the state line, it becomes NY 45. Chestnut Ridge Road runs north through Chestnut Ridge, parallel to the Garden State Parkway. NY 45 crosses the New York Thruway (I-87/I-287), but there is no interchange. In Spring Valley, it is known as South Main Street and then changes names to become North Main Street after crossing NY 59. NY 45 continues north to Mount Ivy, where it has an interchange with the Palisades Parkway and then ends at US 202.