For pilgrims to the uttermost part of the earth, mecca is Parque Nacional Tierra del Fuego’s Bahía Lapataia, where RN 3 ends on the Beagle Channel’s north shore. It’s a worthy goal, but sadly most visitors see only the area on and around the highway because most of the park’s mountainous interior, with its alpine lakes, limpid rivers, blue-tinged glaciers, and jagged summits, is closed to public access.
Camping is the only option in the park itself, where there are free sites with little or no infrastructure at Camping Ensenada, Camping Río Pipo, Camping Las Bandurrias, Camping Laguna Verde, and Camping Los Cauquenes. While these are improving, they’re less tidy than the commercial Camping Lago Roca (tel. 02901/43-3313, lagoroca [at] speedy [dot] com [dot] ar, US$4 pp), which has hot showers, a grocery, and the restaurant confitería La Cabaña del Bosque.
At the park entrance on RN 3, the APN has a Centro de Información where it collects a US$14 pp entry fee. Argentine residents pay half.
Several books have useful information on the park, including William Leitch’s South America’s National Parks (Seattle: The Mountaineers, 1990), which is now out of print. Two good hiking guides are the fifth edition of Tim Burford’s Backpacking in Chile & Argentina (Chalfont St Peter, UK: Bradt Publications, 2001) and the fourth edition of Trekking in the Patagonian Andes (Melbourne: Lonely Planet, 2009).
Birders may want to acquire Claudio Venegas Canelo’s Aves de Patagonia y Tierra del Fuego Chileno-Argentina (Punta Arenas: Ediciones de la Universidad de Magallanes, 1986), Ricardo Clark’s Aves de Tierra del Fuego y Cabo de Hornos (Buenos Aires: Literature of Latin America, 1986), or Enrique Couve and Claudio Vidal Ojeda’s bilingual Birds of the Beagle Channel (Punta Arenas: Fantástico Sur Birding & Nature, 2000).
The transportation details provided for Ushuaia  apply to the park as well.