where is the entrance to new vegas in Fallout New Vegas?

Answer 1

The entrance is found within Freeside East Gate, the gate to freeside is southwest of Crimson Caravan Company and south of Freeside's North Gate, both of which should be marked on your map as you go through some of the first missions for factions.

Answer 2

it is in freeside which is north of goodsprings, where you start out. you have to enter freeside and then can enter into new vegas, but only if you have a passport.