Colorado's 'Steel City' is Pueblo, a city located in the south-central part of the state. Pueblo is known for its steel production and is home to the largest steel mill in the western United States. The city has a rich history, having been founded in 1842 as a trading post along the Santa Fe Trail. It was incorporated in 1886 and has since grown to become the most populous city in southern Colorado. Pueblo is also home to several museums, galleries, and other attractions, making it a popular tourist destination.