Cumberland City is a town in Stewart County, Tennessee. The population was 311 at the 2010 census. It is part of the Clarksville, TN — Kentucky Metropolitan Statistical Area.Cumberland City is the site of a TVA Cumberland Fossil Plant along the Cumberland River that provides 2.6 gigawatts of electric power to much of the area, including the cities of Clarksville in Montgomery County and Dickson in Dickson County.The power plant's towers can be seen for at least 30 miles away.