In the historical past Old India covered the followingterritories (west to east):
part of Iran
all of Afghanistan
all of Pakistan
all of Tajikistan
almost half of Tibet
some part of Nepal
all of India
all of Bangladesh
all of Bhutan
all of Burma, Laos, Thailand, Cambodia, Vietnam, Sri Lanka, Malaysia, Indonesia
and last Brunei.
It also refers to various groups of warriors:
the Gurkhas (Nepalese-Mongolian), arguably the best warriors in the world. They were skilled in icy mountain battles of the Himalayas
the Rajasthan militants, who were skilled in desert battles of the Thar desert
the warriors of Punjab, who were skilled in domesticating and using lions and tigers in battle, plus elephants, but it is a myth that they used Indian rhinos in the battles.
It also refers to the time when it was thought that 25 percent of India's religion was each:
Hinduism
Sikhism
Jainism
Buddhism
This term is mainly used in the Himalayas by great scholars, rishis, presits, pundits, and gurus.