Hydnefossen is the highest waterfall in Buskerud measured on total drop.
It is located in the river Hynda (or Hornsbekken) by Hornset in Hemsedal.
The waterfall starts with a vertical drop of 155 meter and continues down the steep slope down to the valley.
For the best views take the road on the Thorsetsiden of Hemsedal or rv 52 between Hemsedal and Gol, as well as the paralell road along rv 52 towards Huso. To get to the paralell road turn to Lykkja (signed) in Ulsåk and after a few km turn right towards Huso (signed).
If you want to visit the top of Hydnefossen then follow the description towards Velsehødn and on the way up or down you can see the waterfall from the side/above.
Next to Hydnefossen, you can also go to Hydnekjaften. There is a viewpoint that is not marked on the map and you have to walk carefully. It is a steep mountainside and you can stand in the very gap to the old woman and look all the way down to the valley floor.
Remember that there are steep mountains, so watch out for each other and remember to think about safety and don't challenge yourself on anything that isn't safe.
All walking is at your own risk and you must check the weather yourself and feel your body if this is something for you. Do not recommend going here on a rainy day because it can be slippery.