Complex sentence: The Shire is named after the Wimmera region in which it occupies the western portion and the LGA lies entirely to the west of the Wimmera River, which actually meanders through another municipality to the east, that is the Rural City of Horsham.
Split into simpler sentences: The Shire is named after the Wimmera region, in which the LGA occupies the western portion. The LGA also lies entirely to the west of the Wimmera River, which actually meanders through another municipality to the east, that is the Rural City of Horsham.