From the top of New Mexico's Valles Caldera National Preserve, the entire Valle Grande – a three-mile-wide volcanic valley with creeks flowing through it in tight, serpentine bends – sprawls westward. Herds of elk scatter in front of trucks like schools of baitfish. Huge bulls high-step across a meadow that looks like Yellowstone, minus the tourists. The anglers who come here in search of San Antonio Creek's clear, trout-filled waters bounce along the rutted roads leading into the 89,000-acre preserve – taking a bit of punishment in advance of their reward. 

Until recently, it would have been nearly impossible to find anyone who'd been inside this 1.3 million-year-old volcano in the Jemez Mountains, let alone fished here. For 140 years, it was owned by several private ranchers, and even its geology – a ring of domes surrounded by the high edges of the crater – seemed intent on keeping people out. Even now, years after the federal government opened this treasure to the public, few people visit despite its proximity to Santa Fe (40 miles).

Lucky fishermen can have a dozen pools to themselves. Unlike other trout streams, the San Antonio's grassy banks are devoid of brush, and the closest possible thing to snag while back casting is the timber hundreds of yards from the water. It was as if the San Antonio had been designed for casting – making it basically fly-fishing's version of a driving range.

Small browns leave the banks and roll on casters' nymphs, their white bellies flashing through the tea-colored water. These fish are small, 12 inches or less, with creamy skin and white-and-black barbs on their fins. They are always hungry thanks to the high-country winter and they bite consistently. The fishing is catch and release, and everyone is required to go through a park orientation.

Anglers generally stop counting after they land their first 20 or so. All that activity gets exhausting and so they lay down and stare up at 11,254-foot Redondo Peak, the second highest point in the Jemez Mountains. Farther downstream, volcanic domes, bristling with rock and pines, rise like coral heads from the floor of the valley. The place feels empty and quiet, yet still full of riverine life.

More information: New Mexico fishing licenses are available at the High Desert Angler in Santa Fe. Fishers can book a hotel room in nearby Los Alamos and make the 20-minute drive.