Southborough is a town in Worcester County, Massachusetts, United States. It incorporates the villages of Cordaville, Fayville, and Southville. Its name is often informally shortened to Southboro, a usage seen on many area signs and maps. At the 2020 census, its population was 10,450 in 3,542 households.

Worcester County is a county in the U.S. state of Massachusetts. At the 2020 census, the population was 862,111, making it the second-most populous county in Massachusetts. It is also the largest county in Massachusetts by geographic area. The largest city and traditional shire town is Worcester. Worcester County is part of the Worcester, MA–CT metropolitan statistical area and the Boston-Worcester-Providence combined statistical area.