Bailley Brook is a long first-order tributary to Tunungwant Creek. It is the only stream of this name in the United States.
Bailley Brook rises about northeast of Limestone, New York in Cattaraugus County and then flows generally west to meet Tunungwant Creek about north of Limestone, New York.
Bailley Brook drains of area, receives about of precipitation, and is about 93.64% forested.