Billings is the most populous city in the U.S. state of Montana, with a population of 117,116 as of the 2020 census. Located in the south-central portion of the state, it is the seat of Yellowstone County and the principal city of the Billings Metropolitan Area, which had a population of 184,167 in the 2020 census. With one of the largest trade areas in the United States, Billings is the trade and distribution center for much of Montana east of the Continental Divide. Billings is also the largest retail destination for much of the same area. The Billings Chamber of Commerce claims the area of commerce covers more than 125,000 square miles (320,000 km2). In 2009, it was estimated to serve over 500,000 people.

Montana is a landlocked state in the Mountain West subregion of the Western United States. It borders Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, and the Canadian provinces of Alberta, British Columbia, and Saskatchewan to the north. It is the fourth-largest state by area, the eighth-least populous state, and the third-least densely populated state. Its capital is Helena, while the most populous city is Billings. The western half of the state contains numerous mountain ranges, while the eastern half is characterized by western prairie terrain and badlands, with smaller mountain ranges found throughout the state.