Belfast is a town in Allegany County, New York, United States. The population was 1,714 at the 2000 census. It was named after the city of Belfast in Northern Ireland.
The first settlers had arrived by 1804.
The town of Belfast was established in 1824 as the town of Orrinsburgh from part of the town of Caneadea. The name was changed to Belfast in 1825 due to the large amount of settlers in the area of Irish descent. The hamlet of Belfast was established as a "mill town" with water power from the Genesee River, which runs across the town. In 1831, the size of the town increased by adding more territory from Caneadea.