Sidney is a city in Cheyenne County, Nebraska, United States. The population was 6,282 at the 2000 census. It is the county seat of Cheyenne County.
The city was named for Sidney Dillon, a railroad attorney. It was founded in 1867 by the Union Pacific and grew up around the military base of Fort Sidney (also known as Sidney Barracks), where soldiers were stationed to guard the transcontinental railroad from potential Indian attacks. The town became the southern terminus of the Sidney Black Hills Stage Road which used Clarke's Bridge (near Bridgeport, Nebraska) to allow military and civilian traffic to reach Fort Robinson, Red Cloud Agency, Spotted Tail Agency, Custer, South Dakota, and Deadwood, South Dakota in the late 1870s and 1880s.
Sidney is located at 41°8′22″N 102°58′42″W / 41.13944°N 102.97833°W / 41.13944; -102.97833 (41.139428, -102.978323).