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 milesThe City of Sidney was recently awarded $48,300 in the third round of grant funding by Ohio EPA’s H2Ohio Rivers Chloride Reduction Grant Program. Read on... Sidney Police