Billings is the largest 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. It has a trade area of over 500,000.

Billings was nicknamed the "Magic City" because of its rapid growth from its founding as a railroad town in March 1882. The nearby Crow and Cheyenne peoples called the city Ammalapáshkuua and É'êxováhtóva respectively. 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 city is experiencing rapid growth and a strong economy; it has had and is continuing to have the largest growth of any city in Montana. Parts of the metro area are seeing hyper growth. From 2000 to 2010 Lockwood, an eastern suburb, saw growth of 57.8%, the largest growth rate of any community in Montana. Billings has avoided the economic downturn that affected most of the nation from 2008 to 2012 as well as the housing bust. With more hotel accommodations than any area within a five-state region, the city hosts a variety of conventions, concerts, sporting events, and other rallies. With the Bakken oil development in eastern Montana and western North Dakota, the largest oil discovery in U.S. history, as well as the Heath shale oil discovery just north of Billings, the city's growth rate stayed high during the shale oil boom. Although the city is growing, its growth rate has diminished markedly with oil price declines in recent years.

Attractions in and around Billings include ZooMontana, Yellowstone Art Museum, Pompey's Pillar, Pictograph Cave, Chief Plenty Coups State Park. Little Bighorn Battlefield National Monument, Bighorn Canyon National Recreation Area, Red Lodge Mountain Resort, the Beartooth Highway, which connects Red Lodge and Yellowstone National Park. The northeast entrance to Yellowstone National Park is a little over 100 miles (160 km) from Billings.