Eau Claire County is a county located in the U.S. state of Wisconsin. As of the 2020 census, the population was 105,710. Its county seat is Eau Claire. The county took its name from the Eau Claire River.

Eau Claire is a city in Eau Claire and Chippewa counties in the U.S. state of Wisconsin. It is the county seat of Eau Claire County. It had a population of 69,421 in 2020, making it the state's eighth-most populous city. It is the principal city of the Eau Claire metropolitan area, locally known as the Chippewa Valley, and is also part of the larger Eau Claire–Menomonie combined statistical area.