Sidney is approximately midway between Glendive, Montana and Williston, North Dakota.

Settlers began arriving in the area in the 1870s, and a post office was established in 1888.

[7] Agriculture became an important part of the region after the Lower Yellowstone Irrigation Project[8] was completed in 1909.

[9] During the Great Depression, Montana artist J. K. Ralston painted a Federal Arts Project mural at the Richland County Courthouse in Sidney.

[5] The area experienced an oil boom and bust in the late 1970s and early 1980s, bringing an influx of people to the town for a short period of time.

Around the start of the 21st century, the town experienced another surge in oil exploration activity.

Sidney experiences a semi-arid climate (Köppen BSk) with long, cold, dry winters and hot, more humid summers.

The museum houses artifacts and archives that detail the history of life in eastern Montana and western North Dakota since the first pioneers arrived in the late 19th century.

[22] There are no institutions of higher education located within the city, but Williston State College in North Dakota is within commuting distance.

The town is served by Sidney-Richland Municipal Airport, located one mile (1.6 km) west of the central business district.

[26] It has scheduled passenger commuter airline flights through Cape Air.

33.7% of all households were made up of individuals, and 12.9% had someone living alone who was 65 years of age or older.

33.0% of all households were made up of individuals, and 15.3% had someone living alone who was 65 years of age or older.