The Taconic State Parkway (often called the Taconic or the TSP and known administratively as New York State Route 987G or NY 987G), is a  divided highway between Kensico Dam and Chatham, the longest parkway in the U.S. state of New York. It follows a generally northward route midway between the Hudson River and the Connecticut and Massachusetts state lines, along the Taconic Mountains. Its southernmost three miles are a surface road; from the junction with the Sprain Brook Parkway northward it is a limited-access highway. It has grade-separated interchanges from that point to its northern terminus; in the three northern counties there are also at-grade intersections, many with closed medians, allowing only right-in/right-out turns. It is open only to passenger vehicles, as with other parkways in New York, and maintained by the state Department of Transportation (NYSDOT), the fourth agency to have that responsibility.