Grand Island is a town and an island in Erie County, New York, USA. As of the 2010 census, the town population is 20,374. This represents an increase of 9.41 rom the 2000 census figure. The current town name derives from the French name La Grande Île, as Grand Island is the largest island in the Niagara River and fourth largest in the state. The phrase La Grande Île appears on the town seal.