[3] The route heads northwest from Winthrop, passing through heavily forested areas of St. Lawrence County.

As NY 420 passes out of Stockholm and into Norfolk, the forests surrounding the highway begin to taper off and give way to small pockets of residences and cultivated fields.

The number of homes along the route begin to increase upon intersecting Plum Brook Road, at which point NY 420 becomes lined with residences for much of its run through north Norfolk.

[3] In Massena, the forests along NY 420 subside slightly as it passes by industrial warehouses and residences.

It curves back to the northwest on the northern riverbank and passes by a mixture of homes and commercial establishments before intersecting NY 37 south of the village center.

The Winthrop–Massena segment of Route 32 did not initially receive a designation; however, by 1926, it had become the northwesternmost portion of NY 56, a highway linking Brighton to Massena via Nicholville and Winthrop.

Also transferred to the state as part of the swap was CR 110 itself, an east–west highway extending from Stockholm Center to Coteys Corner.