South carolina constitution
Article VII: counties and county government
Section 7

The General Assembly shall have the power to alter County lines at any time: Provided, That before any existing County line is altered the question shall be first submitted to the qualified electors of the territory proposed to be taken from one County and given to another, and shall have received two-thirds of the votes cast: Provided, further, That the change shall not reduce the County from which the territory is taken below the limits prescribed in Sections 3, 4 and 5 of this Article: Provided, That the proper proportion of the existing County indebtedness of the section so transferred shall be assumed by the County to which the territory is transferred.