Cerro Dorotea rises 1,460 metres above the Última Esperanza fjord, its northern face grooved by glacial striations that record the retreat of the southern Patagonian ice sheet 12,000 years ago. The mountain stands ten kilometres northwest of Puerto Natales along Route Y-200, a gravel track that cuts through lenga forest and opens onto high steppe where guanaco herds still forage among cushion plants. For a century, arrieros drove cattle over these same slopes to reach the wool estancias of the interior; today, the trails they carved form the backbone of horseback riding trips Puerto Natales outfitters offer from working ranches at the mountain's base. The trailhead sits on private land owned by a Magallanes family that has grazed sheep here since 1948. Foreign visitors pay a 5,000-peso conservation fee to the landowner before accessing the network of bridle paths that spiral toward the summit plateau. Most rides depart between nine and four in the afternoon, when thermal winds from the fjord remain stable and visibility extends across the Paine massif to the east. Guides favour criollo horses descended from Andalusian stock brought by Jesuit missionaries in the eighteenth century—compact animals adapted to scree slopes and sudden weather shifts. The ascent crosses three ecological zones: deciduous lenga and ñirre forest below 600 metres, krummholz scrub to 1,000 metres, and exposed steppe where only coirón grass and calafate bushes survive the wind. From the summit, riders look south over the entire Última Esperanza inlet, a drowned valley carved by the glacier that once fed into the Balmaceda and Serrano icefields. On clear days, the view extends west to the Cordillera Riesco and north to the Sierra Baguales, a 70-kilometre span of intact Patagonian wilderness. The descent follows a separate track through morraines left by the Pleistocene ice, passing stone corrals still used during summer lambing season. Most outfitters pair the Cerro Dorotea summit ride with shorter estancia circuits that explore calafate thickets along the Río Serrano floodplain, where black-necked swans nest in oxbow ponds. These combined itineraries give riders access to both alpine and steppe ecosystems in a single day, a transect that would take weeks on foot. The trails remain open year-round, though winter rides between June and August require layered wool and waterproof gear; summer temperatures rarely exceed 15 degrees Celsius, and wind chill at the summit can drop perceived temperatures below freezing even in January.