Mountainside is located in Union county New jersey with a geographic area of 4.0 square miles. The total population in Mountainside is 6,859 with 47.2% male and 52.8% female. Children under age 5 represent 10.4% of the population, under age 18 equal 22.1% of the population and over age 65 is 28.9% of the population. The median household income is $121,172, per capita income is $59,332. There are a total of 2,521 housing units with 86.3% owner occupied. Education includes 18.3% of residents that are high school graduates and 67.2% with a bachelor's degree or higher. The average temperature in Mountainside in the summer is 73 degrees, and in the winter 34 degrees.
