Rio ( /raɪ.oʊ/) is a village in Columbia County, Wisconsin, United States. The population was 938 at the 2000 census. It is part of the Madison Metropolitan Statistical Area.
Rio is located at 43°26′52″N 89°14′26″W / 43.44778°N 89.24056°W / 43.44778; -89.24056 (43.447914, -89.240557).
According to the United States Census Bureau, the village has a total area of 1.2 square miles (3.2 km²), all of it land. Rio was once a thriving farm community but the number of family farms has decreased tremendously, even while the number of acres being farmed has increased. It is within commuting distance of the capital city of Madison, so some farm land is slowly being converted to housing tracts. The public schools are central to community life and they enjoy a high quality of education due in part to the town's proximity to Madison.