Section 260

No new county shall be formed unless a majority of the qualified electors voting in each part of the county or counties proposed to be dismembered and embraced in the new county, shall separately vote therefor; nor shall the boundary of any judicial district in a county be changed unless at an election held for that purpose, two-thirds of those voting assent thereto. The elections provided for in ​this and the section next preceding shall not be held in any county oftener than once in four years. No new county shall contain less than four hundred square miles; nor shall any existing county be reduced below that size.