Historical Marker

San Agustín Pass

The pass has always provided the best access through three mountain ranges, the Organ to the south and the San Andrés and San Agustín to the north. It was chosen as the route for U.S. 70, one of the nation’s first coast-to-coast highways. Road cuts revealed Tertiary monzonite near the summit. Nearby, Organ Mountain mines yielded copper, lead, silver, gold and zinc. Gypsum sands glisten to the northeast, and to the west is the Rio Grande Valley.