sentences:  About 13.3% of families and 16.7% of the population were below the poverty line, including 24.3% of those under age 18 and 9.9% of those age 65 or over.United States Penitentiary, Marion is located in Southern Precinct in Williamson County.Williamson County lies on the border between humid continental climate (Köppen climate classification "Dfa") and humid subtropical climate (Köppen climate classification "Cfa"), with neither large mountains nor large bodies of water to moderate its temperature.