There are 31 Interstate Highways—9 main routes and 22 auxiliary routes—that exist entirely or partially in the U.S. state of New York, the most of any state.[1] In New York, Interstate Highways are mostly maintained by the New York State Department of Transportation (NYSDOT), with some exceptions. Unlike in some other states, Interstate Highways in New York are not directly referenced by NYSDOT with their number; instead, the letter "I" is suffixed to the number of the route on reference markers and in internal documents. On the surface, there appears to be numerical duplication between several Interstate Highways and state routes—such as I-86 (I-86) and NY 86—but the "I" suffix that is appended to Interstate Highway numbers allows the Interstate Highway and state route to co-exist ("86I" versus "86", respectively).
There are a combined 1,673 miles (2,692 km) of Interstate Highways within New York, which handles about 19 percent of vehicle travel in New York.[2] At approximately 0.50 miles (0.80 km), I-78 is the shortest main Interstate Highway, while I-90 is the longest, spanning 385.88 miles (621.01 km) within New York. I-878, located in Queens, is the shortest active route in the Interstate Highway System at 0.7 miles (1.13 km).
I-84 crosses the New York–Pennsylvania state line near the point where New York, Pennsylvania, and New Jersey meet in the vicinity of Port Jervis. It heads generally east–west across Orange, Dutchess and Putnam counties to the Connecticut state line east of Brewster.[6]
Gap between US 220 and I-81. I-86, known as the Southern Tier Expressway, heads east–west across the Southern Tier from the Pennsylvania state line west of Findley Lake to NY 352 east of downtown Elmira.[4] A second section of I-86 exists in central Broome County, occupying part of a divided highway known as the Quickway.[9] Both pieces of I-86 will eventually be part of a continuous route extending from Erie, Pennsylvania, to Harriman. The I-86 designation is being extended eastward as improvements are made to the existing NY 17 highway.
I-88 serves as a connector between I-81 near Binghamton and the New York State Thruway (I-90) near Schenectady. It parallels NY 7 between the two cities and passes through the city of Oneonta.[6]
I-90 travels from the Pennsylvania state line at Ripley to the Massachusetts border at Canaan. The vast majority of I-90 in New York is part of the New York State Thruway system; the only segment that is not part of the system is a 20-mile (32 km) portion in the city of Albany and its eastern suburbs. Aside from Albany, I-90 also serves Buffalo, Rochester (via I-490), Syracuse, and Utica.[6]
I-281 was a connector highway between I-81 and I-90 that passed through the southeastern suburbs of Syracuse. It was renumbered to I-481 in 1970, possibly to avoid confusion with NY 281, a highway that parallels I-81 some miles south of Syracuse.[17]
I-287 crosses the New Jersey border into New York near Suffern and heads generally southeastward across Rockland and Westchester counties to I-95 in Rye. Most of I-287 in Rockland County overlaps with I-87 and all of I-287 east of Suffern is part of the New York State Thruway system.[6][12]
I-290 is a connector between I-190 in the town of Tonawanda and the New York State Thruway (I-90) near Williamsville. It serves as a northern bypass of Buffalo.[6]
I-481 leaves I-81 south of Syracuse and rejoins its parent in North Syracuse. I-81 serves downtown Syracuse while I-481 bypasses the city to the east, passing through the Syracuse suburbs of Jamesville and DeWitt along the way. It continues north as NY 481.[6]
I-487 was a proposed designation for the Hudson River Expressway, a highway that would have run through the Hudson Valley between the Bronx and Beacon. The project was cancelled by 1971.[21]
I-490 is a loop route off the New York State Thruway (I-90) between the town of Le Roy and the town of Victor. I-90 bypasses the city of Rochester to the south while I-490 serves the city's suburbs and Rochester itself.[6]
I-495, better known as the Long Island Expressway or LIE, extends across Long Island from the western portal of the Queens Midtown Tunnel in Manhattan to Riverhead, Suffolk County.[6] The 2017 route log shows that there is a gap in the designation between I-278 and I-678, where it is designated in between as NY 495, which is incorrect.[23]
I-587 is a short spur linking downtown Kingston to the New York State Thruway (I-87) at exit 19 northwest of the city. It is entirely concurrent with NY 28.[6]
I-687 was a proposed designation for a connector between I-90 and I-87 in northern Albany. The expressway was never constructed due to a lack of funding. I-687 was removed from local and national highway plans in the 1970s.[28] The I-687 designation is currently reserved.[23]
I-690 travels southeast from exit 39 on the New York State Thruway (I-90) in Van Buren and passes through the western suburbs of Syracuse before heading east through the city itself and terminating in DeWitt, where it merges into I-481. I-690 serves the New York State Fairgrounds by way of exits 5–7. It continues north as NY 690.[6]
I-787 is a spur leading from New York State Thruway exit 23 southwest of downtown Albany to the city of Troy north of Albany. In between, I-787 passes through downtown Albany.[6]
I-890 is a loop route off the New York State Thruway (I-90) between Gilderland and Rotterdam. While the Thruway bypasses the city of Schenectady to the south, I-890 directly serves it.[6]