After passing through the Homer Tunnel, the Milford Road emerges into the impressive Cleddau Valley. Here you’ll find one of the most impressive photo stops along the Milford Road: The Chasm.
Bounded by steep mountain ranges on either side, this steep valley is named for the Cleddau River which flows through it. This, in turn, was named by early European explorer John Grono, drawing once again on his home country of Wales for inspiration. The River Cleddau is the body of water which flows into Milford Haven, the harbour after which Grono named Milford Sound.
https://www.milford-sound.co.nz/travel-info/highlights/cleddau-valley/