Allegany is an unincorporated community in Coos County, Oregon, United States, east of Coos Bay. A post office was established there in 1893, and it is unknown why this spelling was chosen rather than the more common form, Allegheny, used for many features in the eastern United States. (The "Allegany" spelling is most common in the state of New York, suggesting the Oregon town's founders were from, or at least familiar with, that area; in contrast, the "Allegheny" spelling is used primarily in Pennsylvania.)