NY 77 begins at a somewhat complicated four-way intersection with NY 78 and NY 98 in Java Center, a hamlet within the Wyoming County town of Java. Here, NY 78 heads east–west through the junction while NY 98 enters the intersection from the south and turns to follow NY 78 east toward an area known as Five Corners. NY 77, meanwhile, continues due north on the path set by NY 98 south of this point. The highway gradually descends through the open fields of Wyoming County, loosely paralleling the Arcade and Attica Railroad for 4 miles (6 km) to the railroad's end outside of North Java. Past this point, NY 77 heads into the town of Sheldon, where it crosses US 20A near the northern town line. In the adjacent town of Bennington, the route serves the small hamlet of the same name, situated around NY 77's junction with NY 354.^[3]

North of Bennington hamlet, the highway traverses some swampy areas on its way into Genesee County, where it crosses the Norfolk Southern Railway's Southern Tier Line at a grade crossing just south of the Darien hamlet of Darien Center. In the small community, located southeast of Darien Lakes State Park, NY 77 intersects the cross-state US 20. Not far to the north of Darien Center is Darien Lake, a sprawling amusement park located on the east side of the highway. The road, however, remains a two-lane highway as it continues north to the town of Pembroke and the village of Corfu, where it intersects NY 33. NY 77 crosses another major east–west route, NY 5, at a junction 2 miles (3.2 km) north of Corfu known locally as Brick House Corners.^[3]

Just beyond that junction, the truck stops and toll plaza associated with exit 48A of the New York State Thruway (I-90) come into view as the road dips slightly in elevation. After connecting to the Thruway's toll plaza, the highway makes its first major bend, turning northeast to pass over the Thruway. Past the Thruway, it once again continues in a more northerly fashion to the hamlet of Indian Falls, a community located on the northern bank of the Tonawanda Creek. NY 77 crosses the creek here, and the falls that give the hamlet its name are visible from the road. North of the falls, the surrounding land becomes mostly fields once again as the route resumes a due north alignment into the town of Alabama. At the small hamlet of Basom, NY 77 intersects Bloomingdale Road, a local road serving the nearby Tonawanda Indian Reservation^[3] that was once part of NY 267.^[4]

Not far from Basom, NY 63 comes in from the east and turns north onto NY 77, starting the only concurrency along the latter route. This ends 1.5 miles (2.4 km) further north in the hamlet of Alabama, where NY 77 turns to the west as NY 63 takes over the northbound route.^[3] The portion of NY 77 from NY 63 to the Niagara County line is maintained by Genesee County as part of CR 12, which continues east of NY 63 along Lewiston, Lockport and North Byron Roads to CR 7 northeast of the village of Elba. This section of NY 77 is the only part that is not maintained by the New York State Department of Transportation (NYSDOT).^[5]

West of NY 63, NY 77 follows Lewiston Road northwest along the southwestern edge of Oak Orchard Swamp and the Iroquois National Wildlife Refuge. As it heads into Niagara County, NY 77 continues to trend slightly northward, running along the northern fringe of the Tonawanda Wildlife Management Area. About 6 miles (10 km) northwest of the county line is the hamlet of McNalls,^[3] which served as the southern terminus of the 1930s incarnation of NY 359.^[6] The route continues on to the eastern suburbs of the city of Lockport, where NY 77 ends at an intersection with NY 31 near the community of Nottingham Estates.^[3]

The northernmost 3.5 miles (5.6 km) of modern NY 77 between Gasport Road at McNalls and what is now NY 31 east of Lockport was originally designated as part of a spur of Route 30, an unsigned legislative route,^[7] by the New York State Legislature in 1914.^[8][9] On March 1, 1921, the spur became part of an extended Route 20.^[10] When the first set of posted routes in New York were assigned in 1924, all of legislative Route 20 west of Rochester was designated as part of NY 3.^[11][12] In the 1930 renumbering of state highways in New York, NY 3 was realigned between Lockport and Gasport to follow modern NY 31. Its former routing from Lockport to McNalls became part of NY 77, a new route assigned in the renumbering that began at US 20 (now US 20A) in Sheldon and passed through Corfu, Alabama, and McNalls on its way to NY 3 in Lockport.^[2][6]

NY 77 was extended south to Arcade c. 1933, following its modern alignment to Java Center and overlapping with NY 98 (via Chaffee and Curriers Roads, both part of NY 98 at the time) between Java Center and Arcade.^[13][14] The extension was short-lived, however, as NY 77 was truncated northward to NY 33 in Corfu c. 1939. Around the same time, NY 98 was realigned to use East Arcade Road between Arcade and NY 78 in Java.^[15][16] NY 77 was reextended southward to Java Center in the late 1950s^[17][18] and along modern NY 98 to the junction of Cattaraugus and East Arcade Roads (the latter then part of NY 98) near Arcade c. 1961.^[18][19] NY 98 was realigned in the early 1960s to follow NY 77 between Arcade and Java Center, resulting in the truncation of NY 77 back to Java Center once again.^[20][21]

NY 77A was a spur of NY 77 in the vicinity of Basom in Genesee County. It was assigned c. 1935^[22][23] and supplanted by an extended NY 267 in the late 1930s.^[16][24]

•   U.S. roads portal

• New York State Route 77 at New York Routes