Lake Unknown is one of New Zealand's most remote and storied alpine lakes, suspended in a hidden hanging valley high above the Dart River near Glenorchy on the South Island. Remarkably, this sizable lake was among the last to be discovered in New Zealand, absent from maps well into the 20th century and not officially documented until the late 1930s. Even during the gold rush era, when the valleys below — including the Beans Burn and the Dart River — were being actively explored and settled, the sheer inaccessibility of this high-altitude lake kept it hidden from the wider world. Ringed by dramatic cliffs, overlooked by peaks including Mount Nox, Mount Chaos, and Minos Peak, and accessible only via steep, trailless terrain through dense forest, Lake Unknown remains one of the most genuinely wild and untouched fishing destinations in the country. Its isolation is not merely a romantic notion — there are no marked trails, no established trip reports in the modern sense, and reaching the lake typically requires multiple days of demanding travel, though a route via a dry creek bed on the eastern face has been identified as a potential single-day approach for experienced backcountry travelers.