is a city in Hamilton County, Indiana, United States. The population was 11,911 at the 2006 census. The Westfield city government estimated in 2008 that the population of the city exceeded 24,000 residents. Westfield is included in the Indianapolis Metropolitan Area.
According to the United States Census Bureau, the town has a total area of 7.6 square miles (19.8 km²), of which, 7.6 square miles (19.8 km²) of it is land and 0.13% is water.