The area that is now known as the city of Taunton was first settled in 1639. Iron ore was discovered in Taunton on the banks of the Two Mile (Forge) River in 1652. After the discovery of the iron ore, a group of 23 people formed a partnership to start up the iron works. The iron works began somewhere between 1652 and 1656. This section of Taunton, the east end, where the iron works were located, became the Town of Raynham. Raynham was incorporated as a town on April 2, 1731.

The Leonard, Jones, Washburn, King, Shaw, Dean, Hall, Gushee, Williams, Gilmore, Andrews, Hathaway, White, Tracy and Knapp are cited as the founding families of Raynham, and their descendants held prominent positions in the town until well into the 20th century. The iron works were the dominant industry in the town for more than two centuries. The importance that was attached to iron works is apparent from the town seal which depicts the iron works along with the date 1652. Ship building was also part of Raynham's early economy. Ridges were cut into the banks of the Taunton River to form cradles for the boats. The ridges of the banks were used as staging and as a means to shore up or brace the ships.

In the 1840s, the railroad ran through Raynham for the first time. The railroad tracks were located in North Raynham and the lines ran from Boston to New Bedford. The advent of the railroad helped the growth of the town.

Today, almost all of the farm land has been developed for housing and business use. Raynham has grown from a town with no street signs and a trolley running through that connected it to the surrounding towns, to a community with a population of over 11,000. Raynham does retain some characteristics of its rural beginnings. It is one of the few towns left in Massachusetts with a private library.