sidneySidney is a city in Shelby County, Ohio, United States, and its county seat. [4] The population was 20,421 at the 2020 census.It is approximately 36 miles (58 km) north of Dayton and 100 milesSidney is located on the southern tip of Vancouver Island on the Saanich Peninsula – just a 20 minute drive from downtown Victoria. Sidney is home to the Sidney Anacortes Ferry Terminal