The 45th Assembly District of Wisconsin is one of 99 districts in the Wisconsin State Assembly. Located in southern Wisconsin, the district comprises most of eastern and central Green County and western and southwestern Rock County. It includes the western half of the city of Beloit, the cities of Evansville and Brodhead, and the villages of Albany and Orfordville. It also contains Beloit College. The district is represented by Democrat Mark Spreitzer, since January 2015.