Last week I drove from Palomas, the Mexican town opposite Columbus, all the way west to Agua Prieta, the twin to Douglas in Arizona. The highway first swings south to skirt the Bootheel and then strikes back north to within a few miles of the border, where it claws its way up the northernmost slopes of the formidable Sierra Madre.
Two narrow lanes squeezed between sheer cliffs and precipitous canyons, the road climbs a half mile in fewer than 10.
There are neither shoulders nor guard-rails; only the little roadside shrines warn of the perils beyond the next hairpin turn.
The blacktop is battered daily by the passage of hundreds of heavy trucks, some of them pulling double trailers up the steep grades. Bad as it is, this is one of just two highways over the mountains for hundreds of miles to the south.
At the top of the pass you cross the Continental Divide at 6,500 feet. From there you can look down and see the black line of the border fence running ruler straight across the plain far below.
The drive back from Douglas on the American side is a cruise-controlled siesta compared to the crossing from Chihuahua to Sonora. On NM 9 you follow the old railroad bed for mile after mile of gentle curves and long, level straightaways.