| d20 | Category | Description |
|---|---|---|
| 1-10 | Nothing | Uneventful travel. No encounter. |
| 11-13 | Environmental | Weather hazard, terrain obstacle, radiation zone, water crossing, collapsed structure |
| 14-16 | Neutral | Traders, travelers, wandering NPCs, animal herds, refugees |
| 17-19 | Hostile | Hostile creatures, bandits, wild animals, feral Ghouls |
| 20 | Discovery | Loot cache, pre-war ruin, unique location, quest hook, mysterious stranger |
Faction-Controlled Tiles use their own encounter tables, which increase the chance of Hostile encounters and add faction-specific results. See World Map Travel for details.