Reedsburg is a city in Sauk County, Wisconsin, United States within the Baraboo micropolitan area. Its population in 2020 was 9,984. The cit…Reedsburg is a city in Sauk County, Wisconsin, United States within the Baraboo micropolitan area. Its population in 2020 was 9,984. The city is surrounded by the Town of Reedsburg and is situated along the Baraboo River.