is a town in Union County, New Jersey, United States. As of the United States 2000 Census, the town population was 29,644.
The area was settled in the late 17th century as part of the Elizabethtown Tract.
Westfield was originally formed as a township on January 27, 1794, from portions of Elizabeth Township, while the area was still part of Essex County, and was incorporated as a one of New Jersey's first 104 townships by an Act of the New Jersey Legislature on February 21, 1798. It became part of the newly-formed Union County on March 19, 1857. Portions of the township have been taken to form Rahway Township (February 27, 1804), Plainfield Township (April 5, 1847), Cranford Township (March 14, 1871), Fanwood Township (March 6, 1878, now known as Scotch Plains), Mountainside (September 25, 1895) and Hillside (April 3, 1913). The Town of Westfield was incorporated on March 4, 1903, replacing Westfield Township. Barely two weeks later, the Borough of Garwood was created from portions of Westfield and Cranford Township, on March 19, 1903.
Westfield is located at (40.649869, -74.343183). Westfield's ZIP Code is 07090.
According to the United States Census Bureau, the town has a total area of 6.8 square miles (17.5 km²), of which, 6.7 square miles (17.4 km²) of it is land and 0.04 square miles (0.1 km²) of it (0.30%) is water.
Six municipalities border the town of Westfield: Mountainside to the north, Springfield Township to the northeast, Garwood and Cranford to the east, Clark to the southeast and Scotch Plains to the west and southwest.