Fallout 3 random encounters

General information
Random encounters in Fallout 3 take the form of unique situations, friendly and/or hostile encounters, or small tasks for the player to perform which are randomly drawn from a broad list of possibilities, and occur in various predetermined encounter areas across the Capital Wasteland. They should not be confused with scripted events that only occur in certain pre-defined locations. Once a random encounter has been activated in a particular area, no other random event will occur in that area. The game can be saved before entering a triggering area, allowing the player to reload the prior save if an activated encounter occurs that is less than desirable.

Unique vs. repeatable
Encounters can be unique or repeatable. Unique encounters can only occur once per play-through whereas repeatable ones can occur at multiple locations.

Encounter types
Random encounter locations are divided into two groups. Some encounters occur only in one group of locations (A in the location table's "Group" column); others occur only in the second group of locations (B in the location table's "Group" column). Very few encounters are available in all locations.

'Type A' encounters, in practical terms, have only one spawn point in the area they can appear, and will usually not leave the immediate area around it unless drawn or forced away from it. The few 'Type A' encounters not set to stay near their spawning point will eventually move to predetermined destinations or patrol routes far across the map. Such movement, however, is often limited to the player being within the same map cell, resulting in the encounter being lost or misplaced when the player leaves the area.

'Type B' encounters are slightly more complex. Though Type B encounters always follow a predetermined patrol route at an encounter location, they have multiple, sometimes less than apparent, spawning points. They can also cover the distance of up to two full-sized map squares (as seen in one's Pipboy). Additionally, due to terrain features, the AI pathing between spawning points (which are also way-points) can create a broad and sometimes elaborate patrol route.

The location information provided in this article is by no means the sole triggering method for the listed encounters. Trigger zones can be as far-reaching as the distance between spawning points, which can result in accidentally and unknowingly triggering and locking an encounter. Most spawn points for encounters are positioned in such a way as to have the encounter appear from around blind corners so as not to have the encounter appear out of thin air, and to have opposing factions appear at the farthest spawn points from one another. Using the wait feature along an encounter's patrol route within view of a spawn point can cause an encounter to be seen appearing abruptly as it moves to where the player is.

List of encounters
The encounters are grouped by living characters or creatures they contain. There are no duplicate listings; if you are looking for an encounter that involves multiple parties, make sure to check all potentially relevant sections.

There are encounters not described below which involve the Talon Company, the Enclave, raiders, and super mutants which are scripted events occurring at specific locations. These encounters are not random. See individual location pages for encounters outside of what is listed below.

Karma-related
Note: If the Lone Wanderer happens to have changed their Karma orientation during the game (either by losing Karma when Karma was positive, or by accomplishing positive acts while Karma was negative), it is possible, although rare, to be attacked by both Regulators and Talon Company mercs, and sometimes even both at the same time.

Random encounter map

 * Yellow dots denote 'Type A' encounter locations.
 * Red dots denote 'Type B' encounters locations (the red lines are way-point connections).
 * Green dots denote Outcast Patrol spawn points (these locations, though not random, duplicate the characters from the Outcast Patrol random encounter with unique characters).

Trigger approaches
Approaches that will trigger the encounters are listed below.

Bugs

 * Enslaving random encounter characters can cause a serious glitch where the game may freeze when attempting to use dialogue with them to either add or remove a slave collar given to you in Paradise Falls.
 * Type B encounters may lose track of assigned patrol routes when they cross another patrol route. They will begin following the waypoints from the other route. Most often seen with Outcast patrols as there are several static Outcast patrol routes that overlap Type B encounter waypoints. Any patrolling encounter can have this happen where random encounter waypoints exist in close proximity.