The Tongariro Alpine crossing is billed as New Zealand's best one day hike. It passes between two important andesitic volcanoes, Tongariro and Ngauruhoe and covers 19.4km in length between Mangatepopo to the west of the mountains and Ketetahi Road end to the north and takes an estimated 7-8 hours to complete. It can be walked in either direction, but the way that I did it is the usual way round to do it because that way you have less climbing to do - the start is much higher than the end point.
Where is it?
The Tongariro crossing is in the Tongariro National Park, which is located in the middle of New Zealand's North Island. This park contains several active volcanoes and has the only "proper" mountains in the North Island - all the nice dramatic sweeping snowy mountain ranges you see in Lord of the Rings are in the Southern Alps on the South Island.
Why does it sometimes have the word Alpine in the name?
In 2007 they changed the name of this crossing to add in the word "Alpine" - it's now the Tongariro ALPINE crossing. This is because too many people did not realise that it was a serious proper mountain hike and would try to do it in completely unsuitable footwear and clothing and then end up needing rescuing. They have big signs up at various places warning you of dire things that would happen, but still people try to do it.
This region is volcanically active and periodically there are events that would be bad to be around (e.g. a lahar or an eruption). There are signs at several points on the crossing saying what to do if it starts erupting. I wouldn't worry though, at the moment it's at a very low Alert Level rating. Check before you go though!
What mountains does it cross?
This hike takes you through a pass between the peaks of Tongariro and Ngauruhoe; both of these are volcanoes that are still periodically active. The crossing itself does not traverse the summit of either of these peaks, but you can do separate side excursions to climb either summit that will add an extra few hours onto your already long hike (you will need to catch an early bus). As the weather was not suitable and I had insufficient time (I walk quite slowly), I did not do this. Because the route covers a very steep uphill route for the first 7km followed by a very slow gentle 12.4km meandering descent, what I plan to do the next time I visit New Zealand is to start from the same place, climb up Ngauruhoe and retrace my steps back to the car. Then I won't be dependent on making it to the bus in time!
How high does the route go?
According to the basic map I got given, the crossing starts at an altitude of around about 1100m and ascends to a little under 1900m (over 6000ft in "old money"), before dropping back to about 750m. So in good weather, it's not at all technically difficult nor challenging to a person of reasonable fitness, and you shouldn't have any problems with the altitude.
How do I book a place on this crossing? / shuttle buses
It's pretty easy to do this trail as you don't need a permit.