The Canyon is a surprising and lush section of the Henderson Track and is worth visiting in its own right. It can be reached by continuing on from Phantom Falls after starting from the Allenvale carpark. It is also possible to include it in a larger loop with Henderson Falls, and start from other locations. This information covers leaving from the Allenvale carpark which is located inland from Lorne.
If you walk the route from Allenvale > Phantom Falls > The Canyon and then return, it is 7.5km in total. Some sections are steep but it's a rewarding hike.
The Canyon is approximately 1km further on from Phantom Falls. There is a sign at the entrance to the Canyon. From here, you need to climb down steep rocks and through an opening that takes you into The Canyon itself.
From here you can explore The Canyon. While walking through, take the time to look up and around and explore the unique nature of the area. Once the trail becomes more ordinary, you can simply turn around and come back through The Canyon or you can continue on to other falls.