Fremont is a city in and the county seat of Sandusky County, Ohio, United States, along the Sandusky River. It is about 35 miles (56 km) southeast of Toledo and 25 miles (40 km) west of Sandusky. The population was 15,930 at the 2020 census.

Sandusky County is a county located in the northwestern part of the U.S. state of Ohio. As of the 2020 census, the population was 58,896. Its county seat and largest city is Fremont. The county was formed on February 12, 1820, from portions of Huron County. The name is derived from the Wyandot word meaning "water". The Sandusky River runs diagonally northeast through the county to its mouth on Sandusky Bay, opening into Lake Erie. Sandusky County compromises the Fremont, OH Micropolitan Statistical Area.