NY 366 begins at an intersection with NY 79 in the city of Ithaca. NY 366 proceeds eastward along Mitchell Street, a two-lane residential street until the intersecting with Ithaca Road, where NY 366 turns to the north on Ithaca. Mitchell Street continues eastward, becoming County Route 110 at the city line. This intersection also served as the former western terminus of NY 393, a designation eliminated in 1980. NY 366 enters the neighborhood of North Belle Sherman, bending northward as Dryden Road after the intersection with Maple Avenue. After the intersection, NY 366 passes along the southern edge of the campus for Cornell University. Heading northeast out of the city, the route intersects with CR 122 at the eastern edge of the campus. After leaving Ithaca, NY 366 enters the town of Dryden, intersecting with the former eastern terminus of NY 392, Forest Home Drive, before entering the hamlet of Varna. Varna consists of a stretch of residential homes on each side of NY 366. NY 366 turns to the northeast through Dryden, intersecting the northern terminus of CR 161 before intersecting with NY 13 after Baker Hill Road. NY 13 and NY 366 form a concurrency on this stretch, as a four-lane arterial known still as Dryden Road. The roads parallel Fall Creek nearby, eventually narrowing in lanes. At the intersection with Main Street, NY 13 continues eastward, while NY 366 turns northward on Main Street, entering the hamlet of Etna. In Etna, NY 366 intersects with CR 109 on the shore of Fall Creek. The two routes are concurrent for less than a block before CR 109 heads eastward towards NY 13. NY 366 parallels Fall Creek through Dryden, sticking as a two-lane local road before entering the town of Freeville. In Freeville, NY 366 retains its Main Street moniker, but becomes a residential street before intersecting with NY 38. This intersection serves as the eastern terminus for NY 366, but the right-of-way continues out of Freeville as CR 105 toward the hamlet of Red Mills.
History
In 1908, the New York State Legislature created Route 9, an unsigned legislative route that ran from the Southern Tier to Bouckville via Ithaca and Cortland. Route 9 exited the city of Ithaca on modern NY 366 and followed it east through Varna and Etna to Freeville, from where it continued southeastward toward Dryden on what is now NY 38. When the first set of posted routes in New York were assigned in 1924, the segment of legislative Route 9 between Varna and Etna became part of NY 13. Unlike Route 9 before it, NY 13 exited Ithaca on Forest Home Drive and bypassed Freeville to the south in favor of a direct alignment between Etna and Dryden. Also assigned at this time was NY 26, a highway that initially extended from Ithaca to Syracuse via Moravia and Skaneateles. NY 26 began in downtown Ithaca and overlapped with NY 13 east to Etna, where it turned northeast to follow old legislative Route 9 to Freeville. Past Freeville, the route continued northward toward Syracuse on modern NY 38. The overlap between NY 13 and NY 26 was eliminated in the late 1920s when NY 26 was truncated to begin at the former east end of the concurrency in Etna. In the 1930 renumbering of state highways in New York, the NY 26 designation was reassigned to another highway off to the east. The southernmost portion of NY 26's former routing between Etna and Freeville was redesignated as NY 366. NY 13 was realigned to bypass the Cornell University grounds to the south on State and Mitchell streets and Ithaca and Dryden roads. Its old alignment through the college became NY 392. In the early 1960s, a new expressway was built along the eastern shore of Cayuga Lake, bypassing downtown Ithaca to the west and north. NY 13 was altered to follow Meadow Street and the freeway between southwestern Ithaca and the town of Dryden while the portion of NY 13's old routing that did not overlap NY 79 became a westward extension of NY 366.
