Sidney is a city in and the county seat of Richland County, Montana, United States, less than west of the North Dakota border. The population was 6,346 at the 2020 census, and was estimated to be 6,031 in 2024. Six-year-old Sidney Walters and his parents were staying with Hiram Otis, the local justice of the peace, and Otis decided that Sidney was a good name for the town. The following year, Montana became a state and Sidney was incorporated in 1911.
Sidney was originally part of Dawson County, but became the county seat of Richland County at its inception in 1914.
Agriculture became an important part of the region after the Lower Yellowstone Irrigation Project was completed in 1909. A dam was built on the river south of Glendive, which diverted water from the river into a main canal, which runs north–south, parallel to the Yellowstone, irrigating land from Glendive north up to Fairview, where it drains into the Missouri River. This project irrigates and serves water to 450 farms, according to the manager of the Lower Yellowstone Irrigation Districts.
During the Great Depression, Montana artist J. K. Ralston painted a Federal Arts Project mural at the Richland County Courthouse in Sidney.
The town received a boost in 1924 when the Holly Sugar Corporation opened up a sugar refinery in Sidney to process locally grown sugar beets.
Geography
thumb|[[Yellowstone River near Sidney]]
Sidney is located in the northeastern part of the state.
According to the United States Census Bureau, the city has a total area of , of which is land and (0.57%) is water.
|source 2 = National Weather Service
Economy
Sidney's economy relies heavily on farming, ranching, and oil production; thus, the surrounding countryside is populated with farms, cattle ranches, and oil/gas extraction sites.
From 1925 to 2023, Sidney was home to a sugar beet factory, the largest employer in the city next to the Sidney Health Center and Sidney Public Schools. The sugar beet factory closed in April 2023.
Arts and culture
The town's museum, the MonDak Heritage Center, was founded in 1967. 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.
Sidney has a public library, the Sidney-Richland County Library.
Government
The town of Sidney has a Mayor and City Council. The City Council has 3 wards, each with 2 councilors. He was unopposed in the November 2025 election.
Education
Sidney has four public schools; one K, 1st, and 2nd grade (Westside Elementary) elementary school, a 3rd, 4th and 5th grade (Central Elementary) Elementary school, a 6-8 Junior High School, and a 9-12 senior high school. Sidney High School's team name is the Eagles.
There are no institutions of higher education located within the city, but Williston State College in North Dakota is within commuting distance. MSU-Billings offers courses through distance education, and Sidney High School has a variety of adult education classes each year.
Media
The city has two community newspapers, The Sidney Herald and The Roundup.
Radio
- KEYZ AM 660
- KGCX FM 93.1
- KTHC FM 95.1
- KYYZ FM 96.1
- KDSR FM 101.1
Infrastructure
The eastern end of Montana Highway 16 joins Highway 200 in Sidney.
The town is served by Sidney-Richland Municipal Airport, located one mile (1.6 km) west of the central business district. It has scheduled passenger commuter airline flights through Cape Air.