Grand island is located in Erie county New york with a geographic area of square miles. The total population in Grand island is 21,287 with 49.6% male and 50.4% female. Children under age 5 represent 6.6% of the population, under age 18 equal 21.2% of the population and over age 65 is 18.5% of the population. The median household income is $90,386, per capita income is $42,689. There are a total of 8,797 housing units with 78.5% owner occupied. Education includes 19.8% of residents that are high school graduates and 42.8% with a bachelor's degree or higher. The average temperature in Grand island in the summer is 70 degrees, and in the winter 27 degrees.