In 1909 work began on the San Luis Southern Railway which would run south from Blanca to the Colorado-New Mexico border, approximately 30 miles. The railroad would connect the towns of New San Acacio, Mesita and Jaroso with the main east-west Denver and Rio Grande Western railroad which ran through Blanca. The trestle was built over Trinchera Creek near what is now the outlet of Smith Reservoir.
When this section of the railroad was abandoned in the 1950's, the trestle remained as a reminder of the passenger and farm freight traffic on the road. Until a new bridge was built over the creek, the trestle served as a bridge on county road 12 for a number of years. In 2004, the trestle was placed on the National Register of Historic Places and on the Colorado Register of Historic Properties. Costilla County has plans to restore the trestle as an historic landmark.
Rattlesnake Trestle gets its nickname from the small canyon it crosses. The area is a wintering ground for the prairie rattlesnake. During the summer months, some of the snakes disperse throughout the area, but many can still be found in the canyon.
