Warren is a town located in Worcester County, Massachusetts. It was first settled in 1664 and was officially incorporated in 1742.
According to the United States Census Bureau, the town has a total area of 71.5 km² (27.6 mi²). 71.3 km² (27.5 mi²) of it is land and 0.2 km² (0.1 mi²) of it is water. The total area is 0.33% water.