NY 133 begins in the
downtown of
Ossining village at an intersection with
US 9 (North Highland Avenue). NY 133 proceeds northeast through Ossining as Croton Avenue, a two-lane commercial street. Winding northeast for several blocks, NY 133 passes multiple apartment buildings before intersecting with the southern terminus of
NY 134 (Dale Avenue). At NY 134, NY 133 turns closer to the east, crossing into a large residential section of Ossining after Linden Avenue. NY 133 winds eastward for several blocks, becoming a commercial/residential street through the town of
Ossining, winding eastward for a distance into a
grade-separated interchange with
NY 9A (the Briarcliff–Peekskill Parkway). After crossing NY 9A, NY 133 continues eastward through Ossining, changing names to Somerstown Road. Now a two-lane residential road, NY 133 bends northeastward, winding through town. At Brookside Road, the route continues northeast, changing names to Somerstown Turnpike. The route remains similar in design for several miles, crossing into the town of
New Castle as a two-lane residential road. NY 133 soon intersects with
NY 100 (Saw Mill River Road), forming a concurrency through New Castle. After the junction, NY 133 and NY 100 enter an interchange with the
Taconic State Parkway, which uses ramps from Campfire Road. After this interchange, the routes enter the hamlet of
Millwood. Just after the former station, NY 133 intersects with
NY 120 (Shingle House Road). At this intersection, NY 133 and NY 120 become concurrent along the street now known as Millwood Road (formerly Shingle House). The two routes wind eastward along a two-lane residential road, passing Gedney Park and leaving the hamlet of Millwood. A short distance to the northeast of Millwood, NY 120 forks east on Quaker Road, while NY 133 continues north on Millwood. NY 133 continues northeast on Millwood Road as a two-lane residential street, winding through the town of New Castle, passing numerous homes for a couple miles. This section is often referred to as "Hawk Alley." After making a turn to the east, NY 133 intersects with Seven Bridges Road (unsigned
County Route 5 (CR 5)). The route winds eastward after CR 5, soon starting the same wind towards the northeast. The residences give way to dense woods, with NY 133 soon entering the village of
Mount Kisco. Just after crossing into Mount Kisco, NY 133 enters an interchange with exit 34 of the
Saw Mill River Parkway. Now known as West Main Street, NY 133 is a two-lane residential street for several blocks, soon bending southeast at Kisco Avenue. Here the name changes to Main Street, and NY 133 passes the
Mount Kisco Metro-North station. Three blocks from the train station, the route enters Feigel Square, where it intersects with
NY 117 (North Bedford Road), which serves as the eastern terminus of NY 133. ==History==