The text on the sign reads:
"Between 1871 and 1873, Bazil Metcalf constructed a toll road from the Dry Cimarron through Tollgate Gap providing one of the few reliable wagon roads between Colorado and northeast New Mexico. This road remained an important commercial route until the Colorado and Southern Railway came through this area in the late 1880's."

Some friends of mine told me about this road. They use it as a way to avoid going over Raton Pass with their motor home when they are traveling. So I decided to travel it when I drove to Denver one time. It is a few miles longer but has wonderful charm that makes the little extra time well worth it.