Wrentham is a town in Norfolk County, Massachusetts, United States. The population was 10,955 at the 2010 census.According to the United States Census Bureau, the town has a total area of 22.9 square miles (59 km2), of which 22.2 square miles (57 km2) is land and 0.7 square miles (1.8 km2) (3.14%) is water.Wrentham was first settled by the English in 1661 and officially incorporated in 1673. It was burned down duringKing Philip's War 1675-1676. For a short time, it was the residence of the educational reformer Horace Mann. It is also known as one of the residences of Helen Keller.