sidneySidney is a city in and the county seat of Cheyenne County, Nebraska, United States. [5] The city is nine miles (14 km) north of the Colorado state . The population was 6,410 at the 2020Sidney (often shortened to Sid) is an English given name deriving from the surname, itself of two different derivations depending on the orins of the family. In some cases a place name, itself