Interstate 25

Interstate 25 (I-25) is an Interstate Highway in the western United States. It is primarily a north–south highway. I-25 stretches from Interstate 10 at Las Cruces, New Mexico, (approximately 25 miles (40 km) north of El Paso, Texas), to Interstate 90 in Buffalo, Wyoming, (approximately 60 miles (97 km) south of the Montana/Wyoming border).

Interstate 25 is the main north–south expressway through Wyoming, Colorado, and New Mexico. From north to south, it passes through or near Casper, Wyoming; Cheyenne, Wyoming; Fort Collins, Colorado; Denver, Colorado; Colorado Springs, Colorado; Pueblo, Colorado; Raton, New Mexico; Las Vegas, New Mexico; Santa Fe, New Mexico; Albuquerque, New Mexico; Socorro, New Mexico; Truth or Consequences, New Mexico and Las Cruces, New Mexico. The I-25 corridor is mainly rural, especially in Wyoming, excluding the Albuquerque, Pueblo, Colorado Springs, and the Denver areas. The part of I-25 in Colorado passes just east of the Front Range of the Rocky Mountains. That stretch was recently involved in a large-scale renovation named the T-REX (TRansportation EXpansion) in Denver, and the COSMIX (Colorado Springs Metropolitan Interstate Expansion). These projects and others in New Mexico were necessitated because these stretches of I-25 were inadequately designed and constructed originally (the pavement was deteriorating rapidly), and also because urban areas like Denver, Colorado Springs, and Albuquerque had tripled and quadrupled in population much earlier than anyone had anticipated back in the 1950s and 1960s. Major highway work for the T-REX project ended on August 22, 2006. The COSMIX project was completed in December 2007. Several other smaller improvement projects for I-25 are still ongoing within Colorado and New Mexico.