Breakdown of На границе офицер спокойно проверил мой паспорт.
Questions & Answers about На границе офицер спокойно проверил мой паспорт.
In Russian, the choice between на and в is mostly about idiomatic usage and how speakers conceptualize the place, not about strict logic.
With граница (border), Russian almost always uses на:
- на границе = at the border
- на таможне = at customs
- на вокзале = at the (train) station
The idea is often: an open area / boundary / surface / checkpoint → на.
В границе is practically never used and would sound wrong in this context.
So you simply have to learn на границе as a fixed, natural combination.