Sidney is a city and county seat of Cheyenne County, Nebraska, United States. The population was 6,757 at the 2010 census.
The city was named for Sidney Dillon, president of the Union Pacific Railroad. 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 home to one of the Old West’s Boot Hill cemeteries; many of those interred there were soldiers from the fort.