NY 90 begins at an intersection with US 11 and NY 41 in the village of Homer. NY 90 proceeds westward along Cayuga Street through the residential center of the village, crossing an intersection with NY 281 (South West Street). After NY 281, NY 90 turns northwest past Glenwood Cemetery and out of the village of Homer into the town of Homer. The route becomes a more rural roadway, soon running along the New York State Route 90 Scenic Byway, turning southwest into a junction with Kinney Gulf Road (CR 111). After a short dart to the southwest, NY 90 leaves Cortland County for Cayuga.