- Aniwa City is a small city located in Marathon County, Wisconsin, United States. It is part of the Wausau Metropolitan Statistical Area. The city has a population of around 260 people as of the 2020 census. Aniwa City is known for its peaceful rural surroundings and close-knit community. The main economic activities in the area include agriculture, forestry, and small local businesses. Aniwa City is a great place for those seeking a quiet and friendly community to live in.