Fort Davis National Historic Site, this is a remnant of the old San Antonio-El Paso road, a stagecoach route.
The Fort's website says this:
" In October 1855, Second Lieutenant Zenas R. Bliss, Eighth U. S.
Infantry, arrived at Fort Davis seventeen days after boarding the
westbound stage in San Antonio. "The Post was the most beautifully
situated of any that I have ever seen. It was in a narrow canyon with
perpendicular sides, the walls of which were about 200 feet in height,"
the young officer later wrote. The necessity for the post, located some
400 miles from San Antonio and 200 miles from Franklin (present-day El
Paso), stemmed from demands for protection on the San Antonio-El Paso
Road. A major link along the most southern route to California, the road
experienced an upsurge of travel in the early 1850s following the
discovery of gold in California. As travel along the road increased, so
did Comanche, Kiowa, and Apache raids into Mexico. Emigrants, mail
carriers and merchants journeyed in constant fear of the raiding
warriors who traveled between Mexico and their homelands to the north.
Despite its picturesque terrain, the buildings were uncomfortable and
difficult to keep warm. "I remember once in a snow storm the snow blew under my bed . . . and it stayed there several days without melting,"
wrote Lieutenant Bliss. In 1856, six stone barracks with thatched roofs
and flagstone floors replaced inadequate enlisted men’s quarters. Along
with the bakery, blacksmith shop, and a warehouse, they were the only
substantial structures of the first fort."
"The first Fort Davis served as a retreat for thousands of emigrants,
freighters, and travelers during the decade preceding the Civil War. It
provided protection for the U. S. Mail and saw the establishment of a
number of stage stations and military posts in the region, including
Fort Stockton and Fort Quitman. It was also an influencing factor in
1859 for the Butterfield Overland Mail to change its route to El Paso.
The new route came through Fort Davis instead of following the road
through the Guadalupe Mountains. Although the post did little to reduce
Indian activity in western Texas, its presence encouraged travel on the
San Antonio-El Paso Road and settlement in the Trans-Pecos region."
Straight off the Fort property to the east on "Fort Street" is the Overland Trail Museum, a community museum showing early life in Jeff Davis County. Definitely worth a stop, visitors not only enjoy the museum's exhibits but the fact that it is along the still unpaved, original San Antonio-El Paso Road.
You can read more about the first Fort Davis (1854-1862) and its history here.http://www.nps.gov/foda/historyculture/firstfortdavis.htm