NY 54 begins at the ramps from interchange 38 with the Southern Tier Expressway (I-86 / NY 17) in the village of Bath, located in town of the same name. A state-maintained continuation of West Washington Street, NY 54 bends to the southeast and under the expressway, crossing over the former Erie Railroad Rochester Division before entering downtown Bath. At the intersection with NY 415 (West Morris Street), the two routes form a concurrency east on West Washington Street. The concurrency begins as a two-lane commercial street, but switches to residential after Cook Street, passing south of Haverling High School. At the junction with Liberty Street, NY 415 turns south along Liberty, while NY 54 turns north. Two blocks after the fork from NY 415, NY 54 intersects with County Route 13 (CR 13; Haverling Street), with the former forking to the northeast along Geneva Street. Crossing northeast along Geneva, NY 54 remains a two-lane residential roadway, passing the Haverling Heights neighborhood to the east before leaving the village of Bath, but remaining in the town of Bath.