The City of Grand Junction is a home rule municipality located in Mesa County, Colorado, USA. According to 2006 Census Bureau estimates, the population of the city is 45,299. Grand Junction is the 15th most populous city in the State of Colorado and the most populous city on the Colorado Western Slope, unofficially serving as the capital of the region. It is the principal city of the Grand Junction Metropolitan Statistical Area which had a population of 129,872 in 2005. It is the county seat of Mesa County. The local television stations serve as a major media source for the region, in the way that those in Denver do for the Denver Metropolitan Area.

The city is located along the north side of the Colorado River, where it receives the Gunnison River from south. The name "Grand" refers to the historical name of the upper Colorado River used by locals in the late 19th and early 20th centuries which was renamed in 1921 and the word 'junction' is from the joining of the Colorado and Gunnison rivers. The city sits near the mid-point of a 30-mile (48 km) arcing valley, known as the Grand Valley, that is a major fruit-growing region, historically home to the Ute people and settled by white farmers in the 1880s. In recent years, several wineries have been established in the area as well. The Colorado National Monument, a series of canyons and mesas similar to the Grand Canyon overlook the city, while most of the area is surrounded by public lands managed by the Bureau of Land Management. Interstate 70 connects the city eastward to Glenwood Springs and Denver.