Castle Hill Basin lies between the Torlesse and Craigieburn mountain ranges in the Canterbury High Country, in New Zealand’s South Island. The Basin is a world class bouldering area with thousands of boulder problems on unique limestone rock formations which formed during the Oligocene age 30-40 million years ago.

The number of quality bouldering problems of all grades is vast, and this database cannot hope to contain them all. Expect many slabs, vertical walls and slight overhangs and plenty of highballs. Holds range from very small edges through to pockets of various sizes and of course slopers of all hideousness. Overall the bouldering can be considered technical and, in many cases, very powerful. Expect to get those little-used muscles exercised. The landings are generally flat and grassy, but a good crashmat set-up is always recommended.

Castle Hill enjoys a reputation for being an extremely technical form of bouldering that completely shuts most visitors down. This is not strictly true, but derived more from the experience foreigners have when they visit Spittle Hill in summer and try the most polished climbs. This reputation does, however, keep Castle Hill as a backwater in terms of the international bouldering scene. It is rare to have more than ten people bouldering at Flock Hill on a weekend. 


Please note:  

  • Dogs are not permitted at any area. All areas are either protected reserves or private farm-land. Farmers have been known to shoot unknown dogs on sight.
  • There is no drinking water and very little shade - bring plenty of water and sun protection with you.
  • Never leave rubbish (finger-tape!)
  • Take care walking around - go easy on the vegetation
  • Please don’t graffiti the rock. No one cares if you were there or not
  • There are public toilets in the Kura Tawhiti Reserve and Cave Stream carparks, and two longdrops at Quantum Field. Please use them! Toilet paper counts as rubbish
  • Stay on existing tracks where possible
  • Fires prohibited at all times
  • Camping is prohibited in all areas - there is a DOC campsite at Cragieburn



Most areas in the Basin are easily accessible, and climbers are welcome.

Flock Hill and Dry Valley are only accessible via foot from the farm gate at Parapet Rock. Please do not enter from Cave Sream Reserve. These fields no longer require special permission before visiting, but please read the Safety Notice and follow instructions/guidelines. 

Altitude of the bouldering areas range between 700-900m.



Like all of New Zealand, the weather in the Basin can be a bit crazy. Check the Castle Hill Village webcam and MetService Canterbury High Country before heading out.


The Basin is a unique and fragile environment, climbers must ensure that any impact on the area is minimal. Please do not leave anything behind - carry out all rubbish, and pack out or bury toilet waste.

Since the rock is limestone, it is prone to polishing and we want to minimise that. A website like this may increase the traffic on those problems, causing them to get polished. But this will not be the case if everyone treats the problems with respect:

  • Clean your shoes
  • Use minimal amounts of chalk
  • Never use chalk on foot holds - chalking up footholds does not help friction, it just polishes the rock at an alarming rate
  • Cleaning holds with water and a toothbrush will remove chalk, rubber and skin from the pores of the rock and ensure it is in the best possible condition for the next person. When the footholds start turning black from rubber, wash them clean again before the rock starts to polish
  • The bouldering here is completely glue free and only a few old chipped problems exist. Let’s keep it that way!


The Five star system

The star-rating system we use is based on an objective system brought to us by Brian Capps (see article on B3bouldering for explanation of origin). Climbs are given stars based on these criteria:

  • Presence and purity of line
  • Obvious start
  • Sharpness / rock quality
  • Landing
  • History
  • Location

Most climbs in the world would be 0 - 2 stars. Only the best of the best are 4 stars, and 5 stars is reserved for the (theoretical) perfect problem, one that is flawless. A three star problem is worth spending a year training for and traveling overseas to send. Anything higher is an absolute must do.

This is not to in any way demerit low or zero star problems, but just help us objectively rate problems without too much hype (that said you may notice that all Derek’s problems have lots of stars. Feel free to comment that you think it should be different).


1 star Captain Contact (ss)

2 stars Millennium

3 stars Lost for Words

4 stars Weapon Omega