New York State Route 9D (NY 9D) is a north–south state highway in the Hudson Valley region of New York in the United States. It starts at the eastern end of the Bear Mountain Bridge at an intersection with U.S. Route 6 (US 6) and US 202 in Westchester County, and follows the eastern shore of the Hudson River for 25.21 miles (40.57 km) to a junction with US 9 north of the village of Wappingers Falls in Dutchess County. While US 9 follows a more inland routing between the bridge and Wappingers Falls, the riverside course of NY 9D takes the route through the village of Cold Spring and the city of Beacon.

The Bear Mountain Bridge, ceremonially named the Purple Heart Veterans Memorial Bridge, is a toll suspension bridge in New York State. It carries US 6 and US 202 across the Hudson River between Bear Mountain State Park in Orange County and Cortlandt in Westchester County. At completion in 1924 it was the longest suspension bridge in the world until this record was surpassed 19 months later by the Benjamin Franklin Bridge between Philadelphia and Camden, New Jersey. Like the Williamsburg Bridge in New York City, the approach spans of the Bear Mountain Bridge are unsuspended; only its main span is suspended by cables.