RATON PASS
This is an awsome spot to stop at, take plenty of pictures and learn its history.
The Raton Pass can approached from I-25 North bound at the Colorado-New Mexico border.
Please make sure to take a moment and read the signs located just off the road that are full of history.
Here are some links to get more information on the Raton Pass:
Raton Pass in wikipedia
Raton Pass History
Santa Fe Trail Map
There are much more information out there but is not the same until you actually visit the site and enjoy the view.