While the village of Northville developed within the borders of Plymouth Township from the 1820s, Northville Township itself did not exist until 1898. At that time, local residents, allegedly feeling slighted by Plymouth Township officials being more focused on Plymouth Village, decided to split off into a separate township. In this way, the former Plymouth "SuperTownship" (which formerly included all of Canton, Plymouth, and Northville Townships) became split into Plymouth Township and Northville Township.

SOURCE:  Wikipedia