Grand Junction is a home rule municipality that is the seat of government and largest city of Mesa County, Colorado, United States. Grand Junction's population was 65,560 at the 2020 United States Census, making it the most populous city in western Colorado and the 17th most populous Colorado municipality overall. As western Colorado's largest city, Grand Junction is the economic and cultural center of the Western Slope region. The city is also a transportation hub, as it is situated at the convergence of Interstate 70 and U.S. Highway 50, and is the largest city between Denver, Colorado and Salt Lake City, Utah. It is also the junction between two major branches of the Denver & Rio Grande Western Railroad. Grand Junction is also a prominent college town, home to Colorado Mesa University. Grand Junction is the principal city of the Grand Junction metropolitan area, which had over 150,000 residents in 2020. The city is located in the heart of the Grand Valley, a large Colorado River valley stretching over 30 miles east-to-west and 5 miles north-to-south. This valley is the most densely populated area in Colorado outside of the Front Range Urban Corridor.