Ky. Rev. Stat. § 67.280
Where the two (2) old counties were in the same representative, senatorial, judicial circuit, congressional, or railroad commissioner district or districts, the new county shall remain in the same district or districts. Where the two (2) old counties were not in the same district or districts, the new county shall be placed in the following district or districts: In the representative, senatorial, judicial circuit, congressional, or railroad commissioner district or districts, respectively, in which the old county, having the largest population, was located; provided, that if each of the two (2) old counties was a separate district the new county shall be divided into two (2) such districts, each district to be coterminous with the boundary lines of the old counties; provided further, that if any of the election districts formed under the provisions of KRS 67.190 to 67.270 as a result of county consolidation are in violation of the requirements of the Constitution, such consolidation shall not be effective unless the General Assembly, at its first session after the consolidation, shall redistrict the state in compliance with the provisions of the Constitution.
KRS 67.280