The trail
The trail to Cajón del Azul starts at the Wharton trailhead, about 15 km from El Bolsón, and takes roughly 3 to 4 hours one way through lenga and coihue forest alongside the Azul river, whose turquoise colour comes from its glacial origin. The elevation gain is moderate, with a few short climbs, and the trail is well marked and busy in high season.
The refuge
At the end of the trail, a stone-walled canyon narrows around the river just before the Cajón del Azul refuge, run by the same family for decades, offering home-cooked meals, shared dorms and camping space. Many hikers do it as a there-and-back day trip, but staying overnight lets you see the canyon without the crowd that arrives mid-morning.
When to go
November to April, when the trail is snow-free; the refuge usually opens for that period and closes in winter. Bring water (though there are streams along the way), sunscreen and hiking shoes, since the last stretch has loose rock.