New York State Route 17

New York State Route 17 (NY 17) is a major state highway that extends for 397 miles (638.91 km) through the Southern Tier and Downstate regions of New York in the United States. It begins at the Pennsylvania state line in Mina and runs east as a limited-access highway, following the Southern Tier Expressway to Binghamton and the Quickway from Binghamton east to Woodbury. At Woodbury, the route turns south to become a local arterial, eventually following the Orange Turnpike to the New Jersey state line near Suffern. The portion of NY 17 west of Woodbury is in the process of being upgraded to Interstate 86, and as of February 2025, the routes are concurrent from the Pennsylvania border to Vestal and from Kirkwood to Windsor.

At 397 miles (639 km), NY 17 is the longest state route in New York, and is the second-longest highway of any kind in the state, behind only the New York State Thruway. It serves 11 counties, passes through the cities of Salamanca, Olean, Corning, Elmira, and Binghamton, and enters the vicinity of several others, including Jamestown and Middletown. As it proceeds across the state, it intersects many of New York's major Interstate and U.S. Highways, including U.S. Route 219 (US 219) in Salamanca, I-390 in Avoca, I-99 and US 15 near Corning, I-81 and US 11 in Binghamton, I-84 and US 6 near Middletown, and I-87 in Woodbury. Aside from a brief concurrency with the Thruway near Hillburn, the route is maintained by the New York State Department of Transportation, including a portion in the vicinity of Waverly that is physically located in Pennsylvania.

Initially part of an auto trail called the Liberty Highway, the route was added to the state highway system in 1924, extending from Westfield to Suffern via at-grade highways. As traffic demand surged, it was moved onto the Quickway and the Southern Tier Expressway as limited-access sections of both were completed from the 1950s to the 1990s. In 1998, all of NY 17 between the Pennsylvania state line and Woodbury was designated as "Future I-86". The westernmost 177 miles (285 km) of the route was designated as I-86 one year later, and the designation has been gradually extended eastward as sections of NY 17 were improved to Interstate Highway standards. Prior to the I-86 designation, NY 17 was part of a multi-state Route 17 along with New Jersey Route 17 and the former Pennsylvania Route 17.

NY 17 begins as a freeway at the point where I-86 crosses the New York–Pennsylvania border in Mina, Chautauqua County. I-86 heads westward from there to its western terminus at I-90. I-86 and NY 17 continue eastward through the Southern Tier, encountering NY 426 (exit 4) a short distance from the state line prior to meeting NY 76 (exit 6) south of Sherman. East of exit 8 (NY 394), I-86 and NY 17 cross Chautauqua Lake and follow the lake shore eastward to Jamestown, where it connects to NY 60 at exit 12 due north of the city. East of the city, the freeway meets US 62 at exit 14 and is joined by the old Erie Railroad line, which parallels the freeway as it heads across southern New York.

Between exits 17 and 18 (NY 280), I-86 and NY 17 cross the Allegheny Reservoir near its northernmost extent. Past NY 280, the freeway runs adjacent to the northern extent of the Allegany State Park and follows the reservoir and the connecting Allegheny River eastward to Salamanca. Near downtown Salamanca, I-86 and NY 17 meet US 219 (exit 21). US 219 joins the freeway east to exit 23 near Carrollton, where it splits from I-86 and NY 17 and heads toward Bradford, Pennsylvania, forming the eastern edge of the state park as it heads south. Meanwhile, the freeway continues east to Olean, where it meets NY 417 (a previous alignment of NY 17) at exit 24 west of town and NY 16 (exit 27) north of the area.

Past Olean, the route drifts northward away from Pennsylvania toward Hornell, where I-86 and NY 17 intersect NY 36 (exit 34). To the east in Avoca, the Southern Tier Expressway meets I-390 at exit 36. I-86 and NY 17 southeast from the junction, passing through Bath on its way an interchange with I-99 and US 15 in Painted Post (exit 44). Here, I-99 and US 15 begin and head south toward Pennsylvania, while I-86 and NY 17 continue east through Corning to the city of Elmira.

From Elmira to Binghamton, NY 17, the Erie Railroad (now operated by Norfolk Southern as the Southern Tier Line), and its old alignments generally stay close together. They follow the Chemung River to exit 60 (US 220 in South Waverly, Pennsylvania) and the Susquehanna River from east of exit 61 (Waverly, New York) to Binghamton; on the latter section, both NY 17C and NY 434 are old NY 17. Between the two rivers, which intersect in Pennsylvania, the general corridor runs just north of the state line in New York. NY 17 itself crosses into Pennsylvania for approximately 1 mile (1.6 km) between a point west of exit 60 and a point west of exit 61; additionally, all the ramps at exit 60 and portions of the eastbound ramps at exits 59A and 61 are in Pennsylvania. Despite being in Pennsylvania, it is still signed as NY 17, and these roadways are still maintained by the New York State Department of Transportation. At the Tioga County line near Waverly, I-86 temporarily terminates as NY 17 continues eastward toward Binghamton.

Near downtown Binghamton, NY 17 goes around the side of Prospect Mountain at what is locally known as "kamikaze curve". Heading eastbound, the freeway curves sharply left around the hillside, splits into ramps to I-81 north and south, and curves right to merge into I-81 south as it passes over the Chenango River. From that point east and southeast about 5 miles (8.0 km), I-81 and NY 17 run concurrently. NY 17 splits from I-81, the Erie Railroad and the Susquehanna River to the east into Stilson Hollow; from this split (exit 75) to its end, most of NY 17 does not follow the Erie Railroad, which crosses into Pennsylvania several times.