Concept:
Hemis festival is one of the most famous Buddhist festivals celebrated in Ladakh.
It is celebrated at Hemis Monastery, which is one of the important monasteries of Ladakh.
Step 1: Understand the festival.
Hemis festival is celebrated in honour of Guru Padmasambhava, who is also known as Guru Rinpoche.
He played an important role in spreading Buddhism in the Himalayan region.
Step 2: Connect the festival with place.
The Hemis Monastery is located in Ladakh.
Therefore, the Hemis festival is directly associated with Ladakh.
Step 3: Final conclusion.
Hence, the correct answer is:
\[
\boxed{\text{Ladakh}}
\]