The map is split into a PvE half and a PvP half. This page covers what each ruleset allows, where the border is, how it is marked, and what changes at wipe.
On the in-game map screen it appears as a dashed orange line across the map. In the world it is a row of evenly spaced glowing orange spheres running the full width of the map. The HUD shows which side you are on: green for PvE, red for PvP, amber while crossing.

