I-25

About I-25

Also known as Pan American Freeway.

From Las Cruces, NM (I-10) to Buffalo, WY (I-90)

Interstate 25 is a major north-south route through the Rocky Mountain region, running about 1,063 miles from Las Cruces, New Mexico, to Buffalo, Wyoming. It crosses New Mexico, Colorado, and Wyoming, following the eastern edge of the Rockies along the historic corridor used by earlier roads and trails. The route ties together the largest cities of the Mountain West interior.

From its southern terminus at I-10 in Las Cruces, the route runs up the Rio Grande valley through Albuquerque, climbs over Raton Pass into Colorado, and serves the Front Range cities of Pueblo, Colorado Springs, Denver, and Fort Collins. It continues north into Wyoming through Cheyenne and Casper before ending at I-90 near Buffalo.

The corridor sits at high elevation for much of its length, with Raton Pass on the New Mexico-Colorado border and the Front Range urban stretch through Denver among its most heavily traveled and weather-sensitive segments. It serves as the spine of settlement along the eastern base of the southern and central Rockies.

State-by-state mileage

State	Miles
New Mexico	462.1
Colorado	298.9
Wyoming	300.9
Total	1,061.9

History

I-25 was part of the Interstate plan approved in 1957 and was built over the following decades along an alignment that broadly follows older routes such as US 85 and the Santa Fe Trail corridor over Raton Pass. Construction tied together a region whose cities had grown along the railroad and earlier highway lines.

Urban segments through Denver and Colorado Springs were repeatedly widened and reconstructed as the Front Range population grew, while the rural Wyoming sections remained more lightly traveled.

Major cities and places

Notable features

• Raton Pass on the New Mexico-Colorado line

Did you know

• Runs along the eastern front of the Rocky Mountains for its full length.
• Crosses Raton Pass between New Mexico and Colorado at high elevation.
• Serves the Colorado Front Range cities from Pueblo north to Fort Collins.
• Northern terminus is at I-90 near Buffalo, Wyoming.