Humboldt Falls is near the end of Lower Hollyford Road in Fiordland. The falls are one of the highest in NZ at 275 metres. Of the very high falls in NZ, it is the most accessible. The track is an easy 80-metre climb over 600 metres through the rainforest to a viewpoint, and it only takes about 30 minutes from the car park and back. By contrast, Sutherland Falls, at 580 metres, is halfway along the Milford Track, while even higher falls, Browne (836 metres), Chamberlain (700 metres), and Lake Unkown (680 metres) are remote.
The only downside is the viewpoint is about 300 metres from the waterfall. You get a great sense of the height, but it does lack impact.
It is also a very short walk from the car park to the road end and the start of the Hollyford Track to Martins Bay on the West Coast. An easy half-day option is a four-hour walk on the track to Hidden Falls and back. You can do the multiday Hollyford as a guided walk or as an old-fashioned tramp that takes in the famously muddy Demon Trail along the side of Lake McKerrow / Whakatipu Waitai.
Another even tougher option is the Pyke Big Bay Route. This is lightly marked near wilderness along the Pyke Valley to Big Bay, north of Martins Bay. You can link the two as a loop for obscure hardcore tramping bragging rights!
