NY 81 proceeds eastward through Rennselaerville, as a two-lane rural roadway, paralleling and crossing some power lines.

Paralleling a nearby creek, CR 67 forks to the southeast, while NY 81 continues on its right-of-way through Durham.

NY 81 bends northeastward, intersecting with the northern terminus of CR 75, where it turns eastward into the town of Greenville.

Making a dart eastward, NY 81 turns to the southeast past the hamlet of Surprise, where the route becomes a rural two-lane roadway once again.

[3] After CR 26, NY 81 crosses over the New York State Thruway (I-87) then parallels another former alignment of itself.

It originally began at US 9W in the town of Coxsackie and ended at NY 30 in the village of Middleburgh.