what county is rochester indiana in?
Sponsored Topics. Rochester is a city in and the county seat of Fulton County, Indiana, United States. The population was 6,414 at the 2000 census. Rochester is located at 41Â°3â²43â³N 86Â°12â²24â³W / 41.06194Â°N 86.20667Â°W / 41.06194; -86.20667 (41.061883, -86.206727).