At the time, it began at the New Jersey state line in Rockland County and followed modern US 9W north to Albany.

North of Stamford in Schoharie County, NY 10 turns northeast, bypassing the 2,900-foot (880 m) tall Mine Hill, home to the source of the west branch of the Delaware.

At the northern edge of the hill, NY 10 curves back to the northwest to serve the Jefferson hamlet of the same name.

[3] Between Cobleskill and Sharon Springs, NY 10 proceeds northwest through rural terrain once more, with the points of interest limited to a small number of hamlets.

In Sharon Springs, a village situated in northwest Schoharie County, NY 10 intersects US 20.

[3] Downtown, maintenance of NY 10 shifts from the New York State Department of Transportation (NYSDOT) to the village at Mohawk Street.

The highway remains locally owned for three blocks to Incinerator Road, where the route becomes state-maintained once more.

North of Incinerator Road, the route passes under the Thruway before crossing into the neighboring village of Palatine Bridge at the midpoint of the Mohawk River.

The two routes join for roughly 1.5 miles (2.4 km) before separating as the roadway crosses over the Blue Line into Adirondack Park.

[3] In 1908, the New York State Legislature designated the primary north–south roadway along the west bank of the Hudson River from the New Jersey state line near New York City to Albany, now largely US 9W, as Route 3, an unsigned legislative route.

[8] In the 1930 renumbering of state highways in New York, NY 10 was significantly reconfigured to begin in Deposit and end at the Canadian border north of Malone.

[2][7] Farther north, the portion from Palatine Bridge to Indian Lake was originally part of NY 80,[9] a route created in the late 1920s.

North of Lake Clear Junction, the route followed the pre-1930 routing of NY 3 from Paul Smiths to Malone and two previously unnumbered highways between Lake Clear Junction and Paul Smiths and from Malone to the Canadian border.