Celje (241 m) is the third largest city in Slovenia. It is a regional center of the Southwestern Lower Styria (Jugozahodna Spodnja Štajerska) and the administrative seat of the municipality of the same name. It is located under the Upper Celje Castle (407 m) at the confluence of the rivers Savinja, Ložnica and Voglajna (with its tributary Hudinja) in the lowest part of the Savinja valley.