U.S. Route 11 (US 11) is a part of the United States Numbered Highway System that runs from New Orleans, Louisiana, to the Canada–United States border at Rouses Point, New York. In the state of New York, US 11 extends for from the Pennsylvania state line south of the Southern Tier city of Binghamton to the Canada–United States border at the North Country village of Rouses Point, where it becomes Route 223 upon entering Quebec. The portion of US 11 south of Watertown follows a mostly north–south alignment and is paralleled by Interstate 81 (I-81) while the part of the route north of Watertown follows a more east–west routing, parallel to but not directly on the St. Lawrence River.

The portion of US 11 in New York passes through the central district of four cities: Binghamton, Cortland, Syracuse, and Watertown. East of Watertown, the route traverses mostly rural terrain and serves only small villages, such as Potsdam, Malone, and Champlain. While the portion of US 11 between the Pennsylvania state line and Watertown is merely an alternate route to I-81, the section east of Watertown is the primary long-distance route across the North Country of New York.

US 11 was designated as part of the 1926 establishment of the U.S. Numbered Highway System. It was first signed in New York in 1927, replacing New York State Route 2 (NY 2), a route assigned three years earlier as part of the creation of the modern New York state route system. The termini of US 11 have more or less remained the same since; however, multiple realignments have occurred along the points in between. One of US 11's three suffixed routes, NY 11C, follows a former routing of US 11.

Route description South of Syracuse US 11 proceeds northwestward through New York from the Pennsylvania border toward Binghamton along the eastern bank of the Susquehanna River. In the town of Kirkwood, it has a grade-separated interchange with County Route 177 (CR 177) between the Conklin–Kirkwood Bridge and CR 177's interchange with I-81, the Interstate's first exit in New York. Most of this stretch is an undivided highway; however, there is a brief divided four-lane section where the highway has a partial Y interchange with NY 990G, a connector to exit 8 on I-81 as well as NY 17 (Future I-86). This connector is part of the former routing of NY 17.

US 11 remains four lanes, now undivided, as it enters the city of Binghamton, serving as the main thoroughfare of the East Side neighborhood. This section is also known as Court Street. The highway then turns southwest, crossing railroad tracks and heading toward downtown. Here, it has an intersection with NY 7 just north of the Tompkins Street Bridge and a folded diamond interchange with NY 363. In the center of downtown, US 11 goes through a roundabout and passes Broome County Courthouse. It then has a junction with NY 434, which terminates at the highway from the south, before crossing the Court Street Bridge, after which it intersects NY 17C and turns north to follow Front Street along the Chenango River. It passes Binghamton High School and goes through a portion of the West Side neighborhood. Later, the highway again interchanges with I-81 (and NY 17) at Interstate exit 13B.

US 11 and I-81 continue to parallel each other as they head north from Binghamton toward Cortland, passing through the hamlets and villages of Hinmans Corners, Glen Castle, Castle Creek, and Whitney Point. Beyond Whitney Point, both I-81 and US 11 begin to follow the Tioughnioga River in a north-northeasterly direction, with US 11 passing through four further settlements along the river (Lisle, Marathon, Messengerville, and Blodgett Mills). Before reaching Cortland, the highway has a direct interchange with I-81 at exit 50 followed immediately by a junction with NY 41, which joins US 11 as the road enters Cortland.

The southernmost portion of US 11 in Cortland is known as Port Watson Street, but it then turns several times onto other streets (Church Street, where it has a brief concurrency with NY 13, and then Clinton Avenue and North Main Street). In downtown Cortland, US 11 passes numerous Cortland County and city offices. It exits downtown via North Main into a primarily residential area, passing the Guthrie Cortland Medical Center. US 11 continues out of the city toward the village of Homer. Another reference route, NY 930Q, connects US 11 and NY  41 to exit 54 of I-81 by two loop ramps. From here, the highway enters Homer, where it is known as Main Street. It has a junction with NY 90 at Cayuga Street, serving as that road's southern terminus. NY 41 then diverges to the northwest at Clinton Street.

US 11 crosses to the east side of I-81 as it leaves the village, passing through a rural area toward the hamlet of Tully Center. In this hamlet, US 11 briefly turns west along a concurrency with NY 80, during which it passes Tully Junior Senior High School. Just before reaching I-81, US 11 turns north again, diverging from NY 80 and running adjacent to the Interstate. Just west of here is the southern terminus of NY 11A, an alternate route for US 11 that runs east of I-81. About north of Tully, the highway reaches its junction with US 20 in the hamlet of LaFayette in the town of the same name. The northbound side of I-81 exit 73 connects to US 11, with the southbound side connecting to US 20. The highway continues through a rural residential area north of the hamlet. It then begins to closely front I-81 before passing under it at exit 78, after which US 11 briefly becomes divided as it traverses Onondaga Reservation. It then enters Nedrow, which marks the beginning of the southern suburbs of Syracuse in the town of Onondaga, where NY 11A again meets US 11 at the former's northern terminus.

The highway follows Salina Street through most of Syracuse and its southern suburbs, passing through residential areas with occasional commercial stretches until reaching downtown. US 11 is parallel to Onondaga Creek for most of its length in Syracuse. It intersects NY 173 in the North Valley neighborhood, then passes through Brighton, where the surroundings remain largely residential with some businesses and churches. In Southwest, US 11 shifts east at Raynor Avenue to follow State Street. As it enters the southern reaches of downtown, the Oncenter complex is a prominent feature on the west side of the highway, with the Everson Museum of Art on the east side. NY 92 terminates from the east as East Genesee Street. Erie Boulevard (NY 5) intersects the highway three blocks beyond here, followed by the western terminus of NY 290 after US 11 crosses under I-81 Bus and I-690. After passing St. Joseph's Hospital in Near Northeast, US 11 switches back to follow Salina Street through the southern part of Washington Square, where it has a junction with NY 298 (Court Street). The route then turns north-northeastward on Wolf Street, which it follows through the remainder of Washington Square and into the northern suburbs of Syracuse.

Syracuse to Watertown As it enters the hamlet of Mattydale, US 11 crosses under the New York State Thruway (I-90) and its name changes from Wolf Street to Brewerton Road. It is a six-lane divided highway on its entire length through Mattydale. As it passes through a commercial area west of Syracuse Hancock International Airport, the road becomes two lanes (later four) with a center turn lane. South Bay Road runs closely parallel to US 11 in this stretch. In North Syracuse, the road reverts to two lanes but becomes four lanes again north of this village, where it crosses under NY 481 and passes through another major commercial area.

Continuing north, US 11 intersects NY 31 in the hamlet of Cicero. It passes through Brewerton, then crosses the Oneida River into Oswego County and passes Fort Brewerton. The next of US 11 run through a light-industrial area on its way to Central Square, where it intersects NY 49. North of here, the highway reaches the hamlet of Hastings and later Colosse, where it intersects NY 69, and Maple View, where it intersects NY 104. In Pulaski, it runs on Salina and Jefferson streets and crosses the Salmon River. After passing through the village of Sandy Creek, the road crosses under I-81 at the exit 134 interchange. It passes through Mannsville and then intersects NY 193 (which terminates at US 11 from the west) at Pierrepont Manor Complex. US 11 continues through a rural area to the village of Adams, where NY 178 also terminates from the west. NY 177 terminates in the same manner in the next hamlet, Adams Center. It has a modified full Y interchange with Kellogg Road, which connects to I-81's exit 149, the last exit accessible directly from US 11 (since it separates from the Interstate just north of Watertown).

Just south of Watertown, NY 232 joins US 11 (and terminates) from the southwest. As it enters Watertown, US 11 curves from a northeast–southwest to north–south alignment and follows Washington Street. The route later turns onto Paddock, Holcomb, Massey, and Leray streets and crosses the Black River via the Court Street Bridge (unrelated to the bridge of the same name that carries US 11 in Binghamton). The highway intersects NY 3 and NY 12 at Arsenal Street. Along Massey Street, it has a concurrency with NY 12 between Arsenal and Main streets and intersects NY 12F at Coffeen Street, which terminates from the west. North of the city, it also has a junction with NY 37 which is that road's western terminus (though it approaches from the west).

North Country US 11 heads northeast from Watertown, passing north of the Adirondack Park and serving several communities—such as the villages of Canton, Malone, and Potsdam—built up along its northern edge. Although the road never crosses the Blue Line delimiting the Adirondack Park, it passes through mostly rural, undeveloped areas nonetheless.

After US 11 passes through Calcium, it parallels the western boundary of Fort Drum, whose main gate is just east of the highway's junction with I-781. Past Fort Drum, the route follows a northeasterly routing across northern Jefferson County and southwestern St. Lawrence County, serving the villages of Evans Mills, Philadelphia, Antwerp, Gouverneur, and Richville and overlapping with NY 26 between Evans Mills and Philadelphia and with NY 812 for several miles north from Gouverneur. US 11 eventually reaches the village of Canton, where it follows Gouverneur and Main streets and intersects NY 68 and NY 310.

At the next village, Potsdam, the highway becomes four lanes and runs along the northern edge of Clarkson University's campus as Maple Street before crossing the Raquette River via a divided alignment known as Sandstone Drive, where it intersects the southern terminus of NY 345 and is paralleled by a railroad bridge. (The former alignment of US 11, the eastern portion of Maple Street, follows a concrete arch bridge over the river south of the current crossing. It is assigned as reference route NY 971U.) After US 11 intersects NY 345 and NY 56, NY 11B breaks from US 11, serving as a southerly alternate route to the U.S. Highway. NY 11B heads due east from Potsdam on Elm Street while US 11 exits to the northeast via Lawrence Avenue. About northeast of Potsdam, US 11 intersects the west end of NY 11C, the northernmost of its three alternate routes in New York. While NY 11C heads to the northeast to reach the hamlets of Brasher Falls and Winthrop, US 11 turns to the east, bypassing both locations to the south. It also intersects the southern terminus of NY 420 and passes through numerous small hamlets such as Sandfordville, Stockholm Center, and Lawrenceville in the towns of Stockholm and Lawrence. NY 11C rejoins US 11 later just west of Lawrenceville.