It is concurrent with its parent route for 1 mile (1.6 km) in the village of Lake George and for three blocks in the hamlet of Elizabethtown.

It follows the Hudson River through northern Saratoga County and southern Warren County, the entirety of Lake George's western shoreline, the west edge of Lake Champlain between Ticonderoga and Westport, and the Ausable River from Keene to Keeseville.

NY 9N is the longest suffixed route in the state, extending for 143.5 miles (230.9 km) from Saratoga Springs to Keeseville.

The route stretches through four counties—Saratoga, Warren, Essex and Clinton—and serves several villages and hamlets, including Lake George, Ticonderoga, and Elizabethtown.

[3] At Bensonhurst Avenue, ownership and maintenance of NY 9N shifts from the city of Saratoga Springs to the New York State Department of Transportation.

[4] As NY 9N exits the city limits and enters the town of Greenfield, it turns to follow a more northerly routing.

Not far to the north, NY 9N enters the village of Corinth, situated on the west bank of the Hudson River.

[3] The portion of NY 9N between Lake George village and Hague is relatively isolated, with mountains lining the western edge of the highway and the lakeshore located to the immediate east.

Along this stretch, NY 9N serves numerous lakeside hamlets, the southernmost of which is Diamond Point, a community just south of the Lake George–Bolton town line.

Here, the route turns back to the north and follows Lake George to the hamlet of Hague, where it meets the northern (signed as the eastern) terminus of NY 8.

NY 9N continues to serve as the lakeside roadway for another 3 miles (5 km) before curving away from the lake and entering Essex County.

Once again, NY 9N serves as the lakeside highway as it follows the western edge of the lake through the hamlet of Crown Point to the peninsula that gives the town its name.

The route continues west, passing over the Bouquet River and entering the hamlet of Elizabethtown, where it rejoins US 9 in the former village's center.

From Elizabethtown to Keeseville, however, Route 22 followed a more westerly alignment via Keene, Jay, and Au Sable Forks.

[14][15] The route was extended once more in November 1953 to its current southern terminus in Saratoga Springs, replacing NY 9K and creating a short overlap with US 9 through Lake George village in the process.