The Town of Smithfield is located in the center of the county.
The region was first settled around 1797. The town was organized in 1807 from land taken from the Town of Cazenovia.
At 7:02 PM on July 8, 2014, Smithfield was struck by an EF2 tornado with peak estimated winds of . The tornado killed four people and destroyed several homes. One house was carried and thrown into another home. The Madison County, New York area last saw an EF2 tornado in 2009; New York state rarely sees tornadoes at or above the EF2 level, and usually only gets about four or five a year. This tornado is believed to be New York state's second-deadliest after a 1989 tornado in Orange County, New York, which killed nine elementary schoolchildren when they were crushed by a falling cafeteria wall.