4 Best Sights in Parque Nacional Nahuel Huapi, The Lake District

The most popular excursion on Lago Nahuel Huapi is the 30-minute boat ride from Puerto Pañuelo on the Península Llao Llao to Isla Victoria, the largest island in the lake. A grove of redwoods transplanted from California thrives in the middle of it. Walk on trails that lead to enchanting views of emerald bays and still lagoons; then board the boat to sail on to the Parque Nacional los Arrayanes. Boats go daily at 10 am and 2 pm (more frequently in high season). The earlier departure includes time for lunch on the island in a cafeteria-style restaurant. The later departure is a shorter trip. Vessels are run by Cau Cau ( Mitre 139, Bariloche  2944/431–372  www.islavictoriayarrayanes.com) and Turisur ( Mitre 219, Bariloche  2944/426–109  www.turisur.com.ar).

A visit to Monte Tronadór requires an all-day outing, covering 170 km (105 miles) round-trip from Bariloche. This 3,658-meter (12,000-foot) extinct volcano—the highest mountain in the northern Lake District—straddles the frontier with Chile, with one peak on either side. Take R258 south along the shores of Lago Gutiérrez and Lago Mascardi. Between the two lakes the road crosses from the Atlantic to the Pacific watershed. At Km 35, turn off onto a road marked "Tronadór" and "Pampa Linda" and continue along the shore of Lago Mascardi, passing a village of the same name. Just beyond the village the road forks, and you continue on a gravel road, R254. Near the bridge the road branches left to Lago Hess and Cascada Los Alerces—a detour you might want to take on your way out.

As you bear right after crossing Los Rápidos Bridge, the road narrows: note that it’s one-way heading up 10 am–2 pm, one-way heading down 4 pm–6 pm, and two-way 7:30 pm–9 am only. The lake ends in a narrow arm (Brazo Tronadór) at the Hotel Tronadór, which has a dock for tours arriving by boat. The road then follows the Río Manso to Pampa Linda, which has a lodge, restaurant, park ranger's office, campsites, and the trailhead for the climb up to the Refugio Otto Meiling at the snow line. Guided horseback rides are organized at the lodge. The road ends 7 km (5 miles) beyond Pampa Linda in a parking lot that was once at the tip of the receding Glaciar Negro (Black Glacier). As the glacier flows down from the mountain, the dirt and black sediment of its lateral moraines are ground up and cover the ice. At first glance it's hard to imagine the tons of ice that lie beneath its black cap.

Lago Nahuel Huapi's entire Quetrihue Peninsula, with its unique forest of arrayanes (myrtle trees), is protected by the Parque Nacional los Arrayanes. These trees absorb so much water through their thin skins that all other vegetation around them dies, leaving a barren forest of peeling cinnamon-colored trunks. A stroll up and down wide wooden steps and walkways is a memorable experience, as light filters through the twisted naked trunks, reflecting a weird red glow. You can make this excursion from the pier at Bahía Brava in Villa La Angostura (or by boat from Bariloche via Isla Victoria). In summer, you can walk (three hours) or cycle, after registering at the Guardaparque office (ranger station) near the pier.  Leave in the morning, as the park entrance closes at 2 pm (11am in winter). A nice combination is to go by boat and return by bike (it's all downhill that way). If returning by boat, buy your return ticket at the pier before you leave.

This national park is notable for having the highest concentration of lakes in Argentina. The largest of them, Lago Nahuel Huapi, covers 897 square km (346 square miles) and has seven arms—the longest of which is 96 km (60 miles) long and 12 km (7 miles) wide—reaching deep into forests of coihue (a native beech), cypress, and lenga (deciduous beech) trees. Intensely blue across its vast expanse and aqua green in its shallow bays, the lake meanders into distant lagoons and misty inlets where the mountains, covered with vegetation at their base, rise straight up out of the water.

Inside the park, nearly every water sport invented can be arranged through local travel agencies, tour offices, or hotels. Boating is particularly popular, with options ranging from a placid Isla Victoria outing to challenging white-water-rafting adventures. Information offices throughout the park can also offer tips about tackling the miles of mountain and woodland trails. Small towns like Villa La Angostura and Villa Traful are excellent destinations for further explorations on foot or horseback. Since most of the park is at a low elevation (under 1,829 meters or 6,000 feet), getting around in winter is not difficult—just cold. Fall foliage, long, warm summer days, and spring flowers are the rewards of other seasons.