Allegany County is one of the 62 counties of the US state of New York. The county seat is Belmont, which is also its largest city. This county has an area of 2,679 km², of which 11 km² are covered by water. The population is 49,927 inhabitants, and its population density is 19 hab / km² according to the national census of the year 2000. This county was founded in 1806.