The hill range separating the state of Manipur from the state of Nagaland is known as:

Geographical Location
The hill range lies in the northeastern part of India, in the region known as Northeast India. It separates the two Indian states of Manipur and Nagaland.

Name of the Hill Range
The hill range that separates Manipur from Nagaland is known as the "Japfü range." It is one of the most prominent ranges in the region and is home to the highest peak in Nagaland, Mount Japfü, which stands at an elevation of 3048 meters.

Significance of the Hill Range
The Japfü range is not only a geographical feature but also holds cultural significance for the local communities living in the region. It is home to the Angami Naga tribe, who consider the region sacred and have preserved their traditional customs and beliefs.

Tourism
The Japfü range is a popular tourist destination and attracts visitors from all over the world. The hill range is a trekker's paradise and offers breathtaking views of the surrounding landscape. It is also home to a diverse range of flora and fauna, including several endemic species.

Conclusion
In conclusion, the hill range separating Manipur from Nagaland is known as the Japfü range. It is an important geographical feature and holds cultural significance for the local communities. The range is also a popular tourist destination and attracts visitors from all over the world.