- Established: 1806
- Population: 49,927 (2000 census)
- County Seat: Belmont
- Tourism Region: Chautauqua-Allegheny
- Information: Allegany County website
- Bordering Counties: Cattaraugus, Livingston, Steuben, McKean Pa., Potter Pa.
- Area code: 585
- Origin of Name: Derived from a Delaware Indian word, applied by settlers of Western New York State to a trail that followed the Allegheny (Allegany) River.
- Incorporated Cities: (none)
- Incorporated Villages: Alfred, Almond*, Andover, Angelica, Belmont, Bolivar, Canaseraga, Cuba, Richburg, Wellsville.
- Towns: Alfred, Allen, Alma, Almond, Amity, Andover, Angelica, Belfast, Birdsall, Bolivar, Burns, Caneadea, Centerville, Clarksville, Cuba, Friendship, Genesee, Granger, Grove, Hume, Independence, New Hudson, Rushford, Scio, Ward, Wellsville, West Almond, Willing, Wirt
- Allegany County is in NYSDOT Region 6, county code 61.
- List of county highways from Empire State Roads.
- Relevant exit guides:
*-Village of Almond also in Steuben County.