Key Summit is an outstanding easy excursion from the Milford Road or a quick side-trip from the Routeburn Track. Its position at the intersection of multiple major valley systems gives Key Summit commanding views of several of Fiordland's spectacular mountain ranges. The popularity of this track is well-deserved.
The climb to Key Summit begins at The Divide trailhead, and starts on the Routeburn Track heading toward the Lake Howden and Lake Mackenzie Huts. The track is well graded and passes through pleasant forest with limited views. After a gradual climb a signed intersection points the way to the Key Summit Track
, which veers above the Routeburn. The smooth track heads uphill via a series of moderate switchbacks.
As the trail emerges from the forest, there are outstanding views down the Hollyford Valley as a taste of the more expansive views to come. Near the top of the climb the trail forks as part of a worthwhile nature loop. The route meanders on the high summit ridge, past beautiful tarns and with many outstanding viewpoints. The turnaround point is the Lake Marian
Viewpoint, where you can just see Lake Marian
perched in a high hanging valley in the Darran Mountains across the Hollyford Valley. After completing the summit nature loop, head back down the way you came.