- Southern Terminus:
- New York-Pennsylvania state line
- Northern Terminus:
- Ulster Avenue (US 9W) and NY 199 in Kingston
- 34.94 miles
- Orange, Sullivan, Ulster
US 209 is a diagonal route extending northeast and southwest between Millersburg, Pennsylvania, and Kingston, New York. It enters New York State multiplexed with US 6. The two routes follows Pike Street and East Main Street through Port Jervis, and then US 209 splits off onto Kingston Avenue. There is a short distance in Port Jervis where US 209 splits into a pair of parallel one-way streets. Northbound traffic follows Culvert Street, while southbound traffic follows Kingston Avenue.
US 209 extends from Port Jervis to the northeast, passing through rural surroundings as a two-lane undivided road. In Kingston, it widens to four lanes and becomes an expressway. There are a few exits, including one for NY 28. It crosses the New York Thruway (I-87), but there is no interchange. US 209 ends at a cloverleaf interchange with Ulster Avenue (US 9W), where the expressway changes designation to become NY 199, the approach to the Rhinecliff Bridge.