Trig M is a short hike between Porters Pass and Castle Hill in Korowai-Torlesse Tussocklands Park, Canterbury, South Island. Porters Pass separates highland Canterbury from the Canterbury Plain and Christchurch. It is the high point of the medium-sized hills southeast of Lake Lyndon.

Trig M is about 12 minutes south of the holiday village of Castle Hill and about 45 minutes south of Arthur’s Pass. By way of Porters Pass, it is 20 minutes northwest of Springfield on the Canterbury Plain. Springfield is the nearest place to buy groceries and petrol.

Along with Helicopter Hill and a loop through the striking Castle Hill (Kura Tawhiti) rocks, it is one of three easy walks/hikes I’ve done in the Castle Hill area. I did it the same day as Helicopter Hill, because it was raining in Arthur’s Pass that day but sunny in this region.

Time

DOC says that the hike takes 90 minutes one-way.

AllTrails users report taking an average of 2 hours 39 minutes for the round-trip.

It took me around 2 hours 30 minutes round-trip, including breaks.

Route

Round-trip, AllTrails reports an elevation gain of 425 meters and a length of 6.6 kilometers.

I hiked via the shorter Starvation Gully route, which is not labeled on the topomap. There is a small amount of space to park beside the trailhead along the highway.

From there, a clearly visible track leads uphill. Starting near Point 1170, the walk becomes pleasantly undulating.

The name ‘Trig M’ is a reference to surveyors’ measurements. I don’t see Trig L or Trig N on the topomap, so maybe M isn’t simply the 13th instance of something.

To shelter from the northwesterly wind, I rested on the east side of Trig M, overlooking Macfarlane Stream.

If 1 is an easy track, and 4 is using hands and feet on exposed rocks, I give this hike a 1.

Hunting

The entire route is in a hunting area. Hunters are forbidden to “discharge firearms near tracks, huts, campsites, road-ends or any other public place.” I have hiked in more than 30 hunting areas, and only passed hunters twice - this wasn’t one of those hikes.

Here is the DOC topomap with all hunting areas visible.

Other pages about this hike

• https://www.doc.govt.nz/globalassets/documents/parks-and-recreation/tracks-and-walks/canterbury/waimakariri/korowai-torlesse.pdf

• https://hikingscenery.com/trig-m-starvation-gully

• https://www.alltrails.com/trail/new-zealand/canterbury/trig-m-track

• https://tramper.nz/1566/trig-m/

Pages about the Coach Stream hike to Trig M (on the lowlands side of Porters Pass)

• https://hikingscenery.com/trig-m-via-coach-stream-track-korowai-torlesse/

• https://www.alltrails.com/trail/new-zealand/canterbury/trig-m-via-coach-stream

• https://www.wildernessmag.co.nz/trip/coach-stream-route-torlesse-korowai-tussocklands-park/

Regional info

• https://www.nzgeo.com/stories/the-rocks-of-castle-hill/

• https://www.stuff.co.nz/pou-tiaki/129923646/new-pou-whenua-unveiled-to-protect-kura-tawhiticastle-hill

• https://www.arthurspass.com/index.php?page=225

This hike seen across Lake Lyndon, from Mt Lyndon-Red Hill