Question

Which ancient kingdoms or empires have names similar to present-day countries in Southeast Asia ? How do their locations compare ?

Answer 1

There as a Gupta Empire in today's northern India, but it did not have the same name.
Then there was the Khmer Empire, which it today's Cambodia (plus a lot more land), but the name is different (the name of the Language is Khmer though).

Then there was a kingdom of Singapora, in today's Singapore, around the same land.

Then there was a Melayu Kingdom -today's Malaysia and Indonesia
and Nam Viet, bigger than today's Vietnam