Date: December 25, 2024 • Elevation: 5,933 feet • Prominence: 1,539 feet • Distance: 4.5 miles • Time: 2 hours, 30 minutes • Gain: 1,580 feet • Conditions: High clouds, calm, sun later on

New Mexico • Main • PB • LoJ

Cox Peak is one of two massive peaks (the other being Mount Riley) that sit dead center in the Potrillo Volcanic Field in southern New Mexico, not far from Las Cruces. These two peaks jut up over 1,500 feet above the terrain, and "stick out" when compared to the other mounds and vents and ridges that compise this field. The peaks can be seen from many dozens of miles away, no matter which direction.

The peaks are plutons, a bolus of solidified magma that rose high enough to break the surface. They have no foothills, and because of their tremendous size, stand out dramatically when compared to the rest of the peaks in the volcanic field, most of which have prominence figures between 200-700 feet. These two things are literally twice as high and as massive as anything else in the surrounding region.

I was here last year at this time, when I climbed a few peaks around Las Cruces, and then climbing Mount Riley as my last peak for that short journey, before heading home to Bisbee. At the time, I pretty much flipped a coin regarding which peak I would climb, deciding I would return later to climb the other one.

For this journey, I left Bisbee this morning before dawn, following routes AZ-80 through Douglas, then NM-80 once inside New Mexico, then NM-9 eastbound across the southern reaches of the state. Being Christmas Day, there was no traffic. I did not see a single vehicle in either direction between the start of NM-9 and the town of Columbus, an 80-mile segment. The day was sunny and clear and very mild for late December.

Here's a neat trivia item: highway NM-9 enters the little town of Animas, merges briefly with route NM-338, then diverges again heading east or west (depending which way you entered the town). It only is concurrent with NM-338 for 0.45 mile, or about 225 feet. It is the only instance of a "duplex" state route in New Mexico. A duplex route is one road with two designations and they are very common in most of the country. But this is the only such case within New Mexico, specifically with its state routes.

I drove another 40 miles or so past Columbus into Doña Ana County (the NM-9 designation ends at the county line; inside the county, it's just a county road, I forget the designation). I could see both peaks looming high above the lower mounds from miles away. I turned north onto County Road 5 at the Potrillo Ranch sign, then followed that north to CR-7, then followed that northeast a couple miles to Gap Tank, as marked on the map.

The roads were in fine shape, a little sandy but generally smooth and maintained. I should mention that the sand was just soft enough to cause my vehicle to yaw on turns. Even motoring at 25-30 miles per hour, if I needed to make a turn, the back end would fishtail slightly. Any faster and I might have run myself off the road.

I planned to hike Cox Peak and nearby East Potrillo Mountain, and being conservative, allotted one day for each, with camping material for the night in between. I did not have a plan which one I would hike first. The weather was very calm and mild, temperatures in the 50s, and some high clouds that muted the sun slightly.

I decided to go for Cox Peak first. It was the bigger of the two and I wanted to tackle it first. I was slightly psyched out by the steep slopes I knew I would have to climb, based on last year's climb of Mount Riley. The slopes on Riley were about as steep as could be before becoming treacherous. I assumed the same to be true for Cox Peak.

I had studied Cox Peak's lines last year and again as I drove in. From the summit, there is a long east ridge that ends and drops steeply down a few hundred feet to the bajada below. However, the south slope of this east ridge looked promising, as best as I could tell from two miles away. That is what I planned to follow.

I got properly dressed and locked the car, then started the trek toward the peak. The first mile crosses open desert, with a rock and gravel tread and spaced-out brush, mainly creosote and ocotillo. The going here was easy and I covered this distance in about 15 minutes, now on the bajada.

The bajada slopes up at a gentle grade, gaining about 400 feet before meeting the base of the mountain itself. This segment went well, too. The ground was a little rockier and the ocotillo a little more densely packed, but I still made good time. I covered this portion in about 15 minutes as well, and I was slightly over a mile from my car.

As I approached the east tip of the ridge, I could see the southern slope in profile and it looked very promising, much more so than I had been expecting. I angled left and circled around to gain this slope on its southern end.

The climb up this slope went very well, and was far easier than I had been expecting. It sloped back very nicely and never once felt remotely treacherous or loose. The flora was spaced out nicely and the rocks held well, now larger and tending to form into small heaps. About two-thirds the way up, I had to go up a slope of talus, the rocks here just piled atop one another. The footing was generally good, but not always. Nevertheless, this went well too. A few more dozens of feet of grunting and I was on top this slope, now atop the eastern ridge! I was absolutely delighted how easy this had gone.

I angled left and started the next segment, a 300-foot gain up another slope to the next higher nubbin on the ridge. This slope behaved very well. It wasn't as rocky as what I had just come up, but it held together well. The rocks here tended to be smaller angular rocks that slid, but as long as I stepped carefully, I had no trouble.

Now above this slope, the summit was up ahead, another 400 feet or so higher. The slope up to it was similar to the one I had just come up. It was steep and a little loose, but very safe. I even found weak paths here. And suddenly, I ran out of mountain to climb. I was on top of Cox Peak!

I was very pleased to have been successful and still excited how easy it had all been. I had been fully mentally prepared for a steep slide-fest like on Mount Riley, but I experienced none of that. This was about as easy and efficient a peak I have ever climbed. And the biggest shocker: it had taken me just one hour, 20 minutes to get here.

The top itself was nothing spectacular: a little cairn with a register, a small pit about two feet deep, and some random rocks and low brush. The clouds were just thick enough to make everything look gray. I snapped a few photos anyway. I was slightly disappointed that the lighting wasn't the best, but given how well the hike had gone, I had no complaints at all. I spent ten minutes up top, looking around and having a snack.

The downhill hike went very well, too. I followed my exact route down, and did not have a single impediment or distraction. The rocks and slopes held together well (a coupe times I slid). I just put one foot in front of the other repeatedly until I was down off the mountain, then onto the bajada, then down off that onto the desert flats and back to my car. The biggest shocker: the outbound hike took me just one hour and five minutes.

I was back to my car just shy of noon, the round trip taking two hours and thirty minutes. I had figured a good 4 hours at least for this peak, but here I was, with a whole day open still. I was riding a high of how well and easy the hike up and down Cox Peak had gone.

The other peak on my agenda, East Potrillo Mountain, rises just across the valley east of Cox and Riley Peaks. This peak does not rise as high and is of a completely different nature than Cox and Riley. It has long ridges and slopes, and the few trip reports I had read mentioned it was an uncomplicated peak to climb. So I decided to climb it today, and not tomorrow.