Middleborough is a town in Plymouth County, Massachusetts, United States. The population was 21,117 as of 2008. For geographic and demographic information on the village of Middleborough Center, please see the article Middleborough Center, Massachusetts. Middleborough is frequently written as Middleboro. In the summer of 2007, Middleborough became the proposed location for a controversial future resort casino, sponsored by the Wampanoag Tribe of Mashpee, Massachusetts.