Old Allegany County Courthouse is a historic courthouse located at Angelica in Allegany County, New York. It was built in 1819 and used until 1892, when the county seat was moved to Belmont, New York. Since then, it has been used as school rooms, church, gymnasium, polling place, and as town offices for the town of Angelica. It is located within the Angelica Park Circle Historic District.
 
It was listed on the National Register of Historic Places in 1972.