Columbus is a city in Columbia County, Wisconsin (mostly) and Dodge County, Wisconsin Counties in the south-central part of the U.S. state of Wisconsin. The population was 5,484 in the 2022 United States census. All of this population resided in the Columbia County portion of the city. Columbus is located about 28 miles (45 km) northeast of Madison on the Crawfish River. The Columbia County portion of the city lies within the Madison Metropolitan Statistical Area while the Dodge County portion is a part of the Milwaukee-Waukesha-Racine CSA. Nearly all of the city is located within the town of Columbus in Columbia County, though a small portion lies within the town of Elba in Dodge County.

Columbia County is a county located in the U.S. state of Wisconsin. As of the 2020 census, the population was 58,490. Its county seat and largest city is Portage. The county was created in 1846 as part of Wisconsin Territory.