diff --git a/src/server/scripts/Northrend/Naxxramas/boss_four_horsemen.cpp b/src/server/scripts/Northrend/Naxxramas/boss_four_horsemen.cpp
index 693253cbb..d73579c25 100644
--- a/src/server/scripts/Northrend/Naxxramas/boss_four_horsemen.cpp
+++ b/src/server/scripts/Northrend/Naxxramas/boss_four_horsemen.cpp
@@ -165,14 +165,16 @@ public:
             me->GetMotionMaster()->MovePoint(currentWaypoint, WaypointPositions[currentWaypoint]);
         }
 
-        bool IsInRoom()
+        void EnterEvadeMode(EvadeReason why) override
         {
-            if (me->GetExactDist(2535.1f, -2968.7f, 241.3f) > 100.0f)
+            if (why == EVADE_REASON_BOUNDARY)
             {
-                EnterEvadeMode();
-                return false;
+                instance->GetCreature(DATA_BARON_RIVENDARE_BOSS)->AI()->EnterEvadeMode(EVADE_REASON_OTHER);
+                instance->GetCreature(DATA_LADY_BLAUMEUX_BOSS)->AI()->EnterEvadeMode(EVADE_REASON_OTHER);
+                instance->GetCreature(DATA_SIR_ZELIEK_BOSS)->AI()->EnterEvadeMode(EVADE_REASON_OTHER);
+                instance->GetCreature(DATA_THANE_KORTHAZZ_BOSS)->AI()->EnterEvadeMode(EVADE_REASON_OTHER);
             }
-            return true;
+            BossAI::EnterEvadeMode();
         }
 
         void Reset() override
@@ -208,7 +210,7 @@ public:
                 me->SetInCombatWithZone();
                 if (!UpdateVictim())
                 {
-                    EnterEvadeMode();
+                    EnterEvadeMode(EVADE_REASON_NO_HOSTILES);
                     return;
                 }
                 if (me->GetEntry() == NPC_LADY_BLAUMEUX || me->GetEntry() == NPC_SIR_ZELIEK)
@@ -278,9 +280,6 @@ public:
                 currentWaypoint = 0;
             }
 
-            if (!IsInRoom())
-                return;
-
             if (movementPhase < MOVE_PHASE_FINISHED || !UpdateVictim())
                 return;
 
diff --git a/src/server/scripts/Northrend/Naxxramas/boss_thaddius.cpp b/src/server/scripts/Northrend/Naxxramas/boss_thaddius.cpp
index 200a3962c..61c609fe4 100644
--- a/src/server/scripts/Northrend/Naxxramas/boss_thaddius.cpp
+++ b/src/server/scripts/Northrend/Naxxramas/boss_thaddius.cpp
@@ -357,8 +357,11 @@ public:
         explicit boss_thaddius_summonAI(Creature* c) : ScriptedAI(c)
         {
             overload = false;
+            instance = c->GetInstanceScript();
+            SetBoundary(instance->GetBossBoundary(BOSS_THADDIUS));
         }
 
+        InstanceScript* instance;
         EventMap events;
         uint32 pullTimer{};
         uint32 visualTimer{};
@@ -383,6 +386,10 @@ public:
         void EnterEvadeMode(EvadeReason why) override
         {
             me->SetControlled(false, UNIT_STATE_STUNNED);
+
+            if (why == EVADE_REASON_BOUNDARY)
+                instance->GetCreature(DATA_THADDIUS_BOSS)->AI()->EnterEvadeMode(EVADE_REASON_BOUNDARY);
+
             ScriptedAI::EnterEvadeMode(why);
         }
 
diff --git a/src/server/scripts/Northrend/Naxxramas/instance_naxxramas.cpp b/src/server/scripts/Northrend/Naxxramas/instance_naxxramas.cpp
index 7d4fa4546..95588a6c1 100644
--- a/src/server/scripts/Northrend/Naxxramas/instance_naxxramas.cpp
+++ b/src/server/scripts/Northrend/Naxxramas/instance_naxxramas.cpp
@@ -25,6 +25,39 @@
 #include "Player.h"
 #include "naxxramas.h"
 
+BossBoundaryData const boundaries =
+{
+    /* Arachnid Quarter */
+    { BOSS_ANUB,      new CircleBoundary(Position(3273.376709f, -3475.876709f), Position(3195.668213f, -3475.930176f)) },
+    { BOSS_FAERLINA,  new RectangleBoundary(3315.0f, 3402.0f, -3727.0f, -3590.0f) },
+    { BOSS_FAERLINA,  new CircleBoundary(Position(3372.68f, -3648.2f), Position(3316.0f, -3704.26f)) },
+    { BOSS_MAEXXNA,   new CircleBoundary(Position(3502.2587f, -3892.1697f), Position(3418.7422f, -3840.271f)) },
+
+    /* Plague Quarter */
+    { BOSS_NOTH,      new RectangleBoundary(2618.0f, 2754.0f, -3557.43f, -3450.0f) },
+    { BOSS_HEIGAN,    new CircleBoundary(Position(2772.57f, -3685.28f), 56.0f) },
+    { BOSS_LOATHEB,   new CircleBoundary(Position(2909.0f, -3997.41f), 57.0f) },
+
+    /* Military Quarter */
+    { BOSS_RAZUVIOUS, new ZRangeBoundary(260.0f, 287.0f) }, // will not chase onto the upper floor
+    { BOSS_GOTHIK,    new RectangleBoundary(2627.0f, 2764.0f, -3440.0f, -3275.0f) },
+    { BOSS_HORSEMAN,  new ParallelogramBoundary(Position(2646.0f, -2959.0f), Position(2529.0f, -3075.0f), Position(2506.0f, -2854.0f)) },
+
+    /* Construct Quarter */
+    { BOSS_PATCHWERK, new CircleBoundary(Position(3204.0f, -3241.4f), 240.0f) },
+    { BOSS_PATCHWERK, new CircleBoundary(Position(3130.8576f, -3210.36f), Position(3085.37f, -3219.85f), true) }, // entrance slime circle blocker
+    { BOSS_GROBBULUS, new CircleBoundary(Position(3204.0f, -3241.4f), 240.0f) },
+    { BOSS_GROBBULUS, new RectangleBoundary(3295.0f, 3340.0f, -3254.2f, -3230.18f, true) }, // entrance door blocker
+    { BOSS_GLUTH,     new CircleBoundary(Position(3293.0f, -3142.0f), 80.0) },
+    { BOSS_GLUTH,     new ParallelogramBoundary(Position(3401.0f, -3149.0f), Position(3261.0f, -3028.0f), Position(3320.0f, -3267.0f)) },
+    { BOSS_GLUTH,     new ZRangeBoundary(285.0f, 310.0f) },
+    { BOSS_THADDIUS,  new ParallelogramBoundary(Position(3478.3f, -3070.0f), Position(3370.0f, -2961.5f), Position(3580.0f, -2961.5f)) },
+
+    /* Frostwyrm Lair */
+    { BOSS_SAPPHIRON, new CircleBoundary(Position(3517.627f, -5255.5f), 110.0) },
+    { BOSS_KELTHUZAD, new CircleBoundary(Position(3716.0f, -5107.0f), 85.0) }
+};
+
 struct LivingPoisonData
 {
     Position Start {};