Kyburg-Buchegg is a former municipality in the district of Bucheggberg, in the canton of Solothurn, Switzerland. On 1 January 2014 the former municipalities of Kyburg-Buchegg, Tscheppach, Brügglen, Aetingen, Aetigkofen, Bibern (SO), Gossliwil, Hessigkofen, Mühledorf (SO), Küttigkofen merged into the new municipality of Buchegg.

Tscheppach is a former municipality in the district of Bucheggberg, in the canton of Solothurn, Switzerland. On 1 January 2014 the former municipalities of Tscheppach, Brügglen, Aetingen, Aetigkofen, Bibern (SO), Gossliwil, Hessigkofen, Mühledorf (SO), Küttigkofen, Kyburg-Buchegg merged into the new municipality of Buchegg.