Interstate 684 (I-684) is a 28.53-mile (45.91 km) auxiliary Interstate Highway in the state of New York in the United States. There is also a short portion in Connecticut with no junctions. The highway connects I-84 with I-287 and the Hutchinson River Parkway, primarily serving commuter traffic to and from the northern suburbs of the New York metropolitan area. Most of the route is in northern Westchester County. The route of the highway was originally designated as part of I-87 from 1968 to 1970. The first section of the roadway opened to traffic in October 1968, and the final segment was completed in December 1974.

Interstate 84 (I-84) is a part of the Interstate Highway System that runs from Dunmore, Pennsylvania, to Sturbridge, Massachusetts, in the eastern United States. In New York, I-84 extends 71.46 miles (115.00 km) from the Pennsylvania state line at Port Jervis to the Connecticut state line east of Brewster. As it heads east–west across the mid Hudson Valley, it goes over two mountain ranges and crosses the Hudson River at the Newburgh–Beacon Bridge.