Parking
Top Forks Hut is the trailhead, not a road car park. Walking in from Kerin Forks Hut is 15 km and 6–8 hours; plan access to the upper Wilkin and book the hut ahead.
Overview
About Lake Castalia Track
Why go
- A remote alpine lake reached through a varied sequence of tarns, grassland and river valleys.
- Lake Diana and Lucidus offer shorter turnarounds on the shared approach.
Heads up
- Several unbridged river and stream crossings; high water can stop the trip.
- The hut itself requires a remote access plan and a full day for the lake return.
Map & elevation
The route
Loading the Mount Aspiring map
Full mapElevation600–1,132 m
Plan your hike
Before you go
Parking
Safety
1 active Mount Aspiring alert
- CautionRob Roy Track: stop at lower lookout during avalanche seasonFrom May through November, end your Rob Roy Track hike at the lower lookout; DOC strongly recommends against continuing to the upper lookout because the track crosses active avalanche paths.Official details
The highest, rockiest slopes around here are a summer buffet for grizzly bears.
Mount Aspiring Tour Guide
Your drive to Lake Castalia Track, narrated.
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Trail guide
Hiking Lake Castalia Track
The full day from the hutThis is an unformed 16 km (10 mi) out-and-back from Top Forks Hut to Lake Castalia.
This is an unformed 16 km (10 mi) out-and-back from Top Forks Hut to Lake Castalia. DOC lists 8 km and 3–4 hours each way; allow about 7–8 hours for the return, before counting the separate journey to the hut. The lake is the reason to go, but this is a serious backcountry route, not a casual extension of the easier lakes nearby.
Boulders, tarns and two easier turnaroundsThe route starts by crossing the South Branch in front of the hut.
The route starts by crossing the South Branch in front of the hut. The shared North Branch approach involves boulder hopping that gets slippery when wet, plus a small side stream that can be awkward to ford. It climbs through forest to Disappearing Tarn, then passes Lake Diana and crosses open grassland toward Lake Lucidus, where part of the way is boardwalked. Diana and Lucidus are shorter turnarounds on this same approach; neither reaches Castalia.
The rougher branch to CastaliaAround the Lucidus boardwalk, the route leaves the easier track, crosses the outlet stream and…
Around the Lucidus boardwalk, the route leaves the easier track, crosses the outlet stream and the North Branch, climbs through alpine vegetation, then crosses the river again. It reaches a snow-grass terrace at the lake outlet. The last 200 m are loose rock. Beyond the formed approach this is unmade route terrain, so expect to choose your line carefully rather than follow a continuous built track.
At the lakeCastalia sits beneath a steep glaciated cirque, with a rocky shore and ice above the basin.
Castalia sits beneath a steep glaciated cirque, with a rocky shore and ice above the basin. There is no constructed viewpoint; the outlet is where the route arrives. The surrounding peak group includes Castor, Pollux, Mercury, Vesta, Juno and Apollo, names attributed to explorer Charles Douglas.
Base and accessThis day walk starts at remote Top Forks Hut, a serviced 16-bunk hut that must be booked.
This day walk starts at remote Top Forks Hut, a serviced 16-bunk hut that must be booked. Its tap water is untreated, so boil it before use. Reaching the hut is a separate trip: the walk from Kerin Forks Hut is 15 km and 6–8 hours, and access to the upper Wilkin needs planning in advance. There is no drive-up car park at this trailhead.
Conditions that change the decisionThe North Branch and its side streams can become impassable after rain; do not cross high water.
The North Branch and its side streams can become impassable after rain; do not cross high water. The route enters complex avalanche terrain beyond Lake Diana, with avalanche danger most common from May to November; DOC does not recommend the overall track in winter and spring. High-level backcountry and river-crossing skills are needed, and dogs are not allowed in the park.
Wildlife
Wildlife in Mount Aspiring
60 sightingsKeaMost seen around 5 PMSighting map
112 sightingsRockwrenMost seen around 8 AMSighting map
26 sightingsYellowheadMost seen around 8 AMSighting map
13 sightingsTūīMost seen around 7 AMSighting map
27 sightingsBellbirdMost seen around 7 AMSighting map
35 sightingsRiflemanMost seen around 8 AMSighting mapSighting maps show where each species has been reported across Mount Aspiring. Wildlife moves, so no sighting is guaranteed.
