Rochester is a city in Olmsted County, Minnesota, United States. It is the county seat. It is located along rolling bluffs on the Zumbro River's south fork in Southeast Minnesota. The population was 121,395 at the 2020 census, and was estimated at 123,624 in 2024, making it the third-most populous city in Minnesota. The Rochester metropolitan area has an estimated 230,000 residents. The city is the home and birthplace of Mayo Clinic.