Mountainside is a town located in the New Jersey region of the United States. During the most recent census, Mountainside had a population of 6,685. Mountainside is the 257th most poplulated city in the New Jersey region, the 5,271st most populated city in the United States and the 26,006th most populated city in the world. Mountainside is in the America/New York timezone which is 4 hours behind UTC. Mountainside adjusts the hour with daylight savings time during the winter months.
Mountainside is located at sea level (46 meters / 151 feet). The closest cities to Mountainside are Westfield (1.7 km / 1.1 miles), Scotch Plains (3.3 km / 2.1 miles), Garwood (3.7 km / 2.3 miles), Fanwood (4.1 km / 2.6 miles) and New Providence (4.7 km / 2.9 miles)