Tenn. Const. art. II, § 4

The apportionment of Senators and Representatives shall be substantially according to population. After each decennial census made by the Bureau of Census of the United States is available the General Assembly shall establish senatorial and representative districts. Nothing in this Section nor in this Article II shall deny to the General Assembly the right at any time to apportion one House of the General Assembly using geography, political subdivisions, substantially equal population and other criteria as factors; provided such apportionment when effective shall comply with the Constitution of the United States as then amended or authoritatively interpreted. If the Constitution of the United States shall require that Legislative apportionment not based entirely on population be approved by vote of the electorate, the General Assembly shall provide for such vote in the apportionment act.