diff --git a/src/cargomonitor.cpp b/src/cargomonitor.cpp
index b1d52d6b18..70d6a9c697 100644
--- a/src/cargomonitor.cpp
+++ b/src/cargomonitor.cpp
@@ -32,12 +32,11 @@ static void ClearCargoMonitoring(CargoMonitorMap &cargo_monitor_map, CompanyID c
 		return;
 	}
 
-	CargoMonitorMap::iterator next;
-	for (CargoMonitorMap::iterator it = cargo_monitor_map.begin(); it != cargo_monitor_map.end(); it = next) {
-		next = it;
-		next++;
+	for (CargoMonitorMap::iterator it = cargo_monitor_map.begin(); it != cargo_monitor_map.end();) {
 		if (DecodeMonitorCompany(it->first) == company) {
-			cargo_monitor_map.erase(it);
+			it = cargo_monitor_map.erase(it);
+		} else {
+			++it;
 		}
 	}
 }
diff --git a/src/cargomonitor.h b/src/cargomonitor.h
index 061a1821a4..cab26785fd 100644
--- a/src/cargomonitor.h
+++ b/src/cargomonitor.h
@@ -17,8 +17,7 @@
 #include "industry.h"
 #include "town.h"
 #include "core/overflowsafe_type.hpp"
-#include <map>
-
+#include "3rdparty/cpp-btree/btree_map.h"
 struct Station;
 
 /**
@@ -32,7 +31,7 @@ struct Station;
 typedef uint32 CargoMonitorID; ///< Type of the cargo monitor number.
 
 /** Map type for storing and updating active cargo monitor numbers and their amounts. */
-typedef std::map<CargoMonitorID, OverflowSafeInt32> CargoMonitorMap;
+typedef btree::btree_map<CargoMonitorID, OverflowSafeInt32> CargoMonitorMap;
 
 extern CargoMonitorMap _cargo_pickups;
 extern CargoMonitorMap _cargo_deliveries;
diff --git a/src/landscape.cpp b/src/landscape.cpp
index 17dfca85a0..18efa43c49 100644
--- a/src/landscape.cpp
+++ b/src/landscape.cpp
@@ -33,8 +33,8 @@
 #include "tunnelbridge_map.h"
 #include "pathfinder/npf/aystar.h"
 #include "saveload/saveload.h"
+#include "3rdparty/cpp-btree/btree_set.h"
 #include <deque>
-#include <set>
 
 #include "table/strings.h"
 #include "table/sprites.h"
@@ -1119,7 +1119,7 @@ static bool FlowRiver(TileIndex spring, TileIndex begin)
 	uint height = TileHeight(begin);
 	if (IsWaterTile(begin)) return DistanceManhattan(spring, begin) > _settings_game.game_creation.min_river_length;
 
-	std::set<TileIndex> marks;
+	btree::btree_set<TileIndex> marks;
 	SET_MARK(begin);
 
 	/* Breadth first search for the closest tile we can flow down to. */
@@ -1156,7 +1156,7 @@ static bool FlowRiver(TileIndex spring, TileIndex begin)
 		/* Maybe we can make a lake. Find the Nth of the considered tiles. */
 		TileIndex lakeCenter = 0;
 		int i = RandomRange(count - 1) + 1;
-		std::set<TileIndex>::const_iterator cit = marks.begin();
+		btree::btree_set<TileIndex>::const_iterator cit = marks.begin();
 		while (--i) cit++;
 		lakeCenter = *cit;
 
diff --git a/src/linkgraph/mcf.cpp b/src/linkgraph/mcf.cpp
index 3a00a2a0e8..2972f4aaf9 100644
--- a/src/linkgraph/mcf.cpp
+++ b/src/linkgraph/mcf.cpp
@@ -3,11 +3,12 @@
 #include "../stdafx.h"
 #include "../core/math_func.hpp"
 #include "mcf.h"
+#include "../3rdparty/cpp-btree/btree_map.h"
 #include <set>
 
 #include "../safeguards.h"
 
-typedef std::map<NodeID, Path *> PathViaMap;
+typedef btree::btree_map<NodeID, Path *> PathViaMap;
 
 /**
  * This is a wrapper around Tannotation* which also stores a cache of GetAnnotation() and GetNode()
diff --git a/src/linkgraph/refresh.h b/src/linkgraph/refresh.h
index 0b834a3e54..da15fbbebd 100644
--- a/src/linkgraph/refresh.h
+++ b/src/linkgraph/refresh.h
@@ -14,9 +14,9 @@
 
 #include "../cargo_type.h"
 #include "../vehicle_base.h"
+#include "../3rdparty/cpp-btree/btree_set.h"
 #include <vector>
 #include <map>
-#include <set>
 
 /**
  * Utility to refresh links a consist will visit.
@@ -67,7 +67,7 @@ protected:
 		 * Default constructor should not be called but has to be visible for
 		 * usage in std::set.
 		 */
-		Hop() {NOT_REACHED();}
+		Hop() {}
 
 		/**
 		 * Real constructor, only use this one.
@@ -80,7 +80,7 @@ protected:
 	};
 
 	typedef std::vector<RefitDesc> RefitList;
-	typedef std::set<Hop> HopSet;
+	typedef btree::btree_set<Hop> HopSet;
 
 	Vehicle *vehicle;           ///< Vehicle for which the links should be refreshed.
 	uint capacities[NUM_CARGO]; ///< Current added capacities per cargo ID in the consist.
diff --git a/src/newgrf.cpp b/src/newgrf.cpp
index 7579636a12..b61db5918e 100644
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -41,7 +41,6 @@
 #include "date_func.h"
 #include "string_func.h"
 #include "network/network.h"
-#include <map>
 #include "smallmap_gui.h"
 #include "genworld.h"
 #include "error.h"
@@ -52,6 +51,8 @@
 #include "table/strings.h"
 #include "table/build_industry.h"
 
+#include "3rdparty/cpp-btree/btree_map.h"
+
 #include "safeguards.h"
 
 /* TTDPatch extended GRF format codec
@@ -90,7 +91,7 @@ private:
 	};
 
 	/** Currently referenceable spritesets */
-	std::map<uint, SpriteSet> spritesets[GSF_END];
+	btree::btree_map<uint, SpriteSet> spritesets[GSF_END];
 
 public:
 	/* Global state */
@@ -347,6 +348,7 @@ struct GRFLocation {
 	uint32 grfid;
 	uint32 nfoline;
 
+	GRFLocation() { }
 	GRFLocation(uint32 grfid, uint32 nfoline) : grfid(grfid), nfoline(nfoline) { }
 
 	bool operator<(const GRFLocation &other) const
@@ -360,8 +362,8 @@ struct GRFLocation {
 	}
 };
 
-static std::map<GRFLocation, SpriteID> _grm_sprites;
-typedef std::map<GRFLocation, byte*> GRFLineToSpriteOverride;
+static btree::btree_map<GRFLocation, SpriteID> _grm_sprites;
+typedef btree::btree_map<GRFLocation, byte*> GRFLineToSpriteOverride;
 static GRFLineToSpriteOverride _grf_line_to_action6_sprite_override;
 
 /**
@@ -5931,7 +5933,7 @@ static void CfgApply(ByteReader *buf)
 	GRFLineToSpriteOverride::iterator it = _grf_line_to_action6_sprite_override.find(location);
 	if (it != _grf_line_to_action6_sprite_override.end()) {
 		free(preload_sprite);
-		preload_sprite = _grf_line_to_action6_sprite_override[location];
+		preload_sprite = it->second;
 	} else {
 		_grf_line_to_action6_sprite_override[location] = preload_sprite;
 	}
@@ -8760,7 +8762,7 @@ static void DecodeSpecialSprite(byte *buf, uint num, GrfLoadingStage stage)
 		FioReadBlock(buf, num);
 	} else {
 		/* Use the preloaded sprite data. */
-		buf = _grf_line_to_action6_sprite_override[location];
+		buf = it->second;
 		grfmsg(7, "DecodeSpecialSprite: Using preloaded pseudo sprite data");
 
 		/* Skip the real (original) content of this action. */
diff --git a/src/spritecache.cpp b/src/spritecache.cpp
index 3ec80b6504..f052f8fd13 100644
--- a/src/spritecache.cpp
+++ b/src/spritecache.cpp
@@ -24,6 +24,8 @@
 #include "table/strings.h"
 #include "table/palette_convert.h"
 
+#include "3rdparty/cpp-btree/btree_map.h"
+
 #include "safeguards.h"
 
 /* Default of 4MB spritecache */
@@ -476,7 +478,7 @@ static void *ReadSprite(const SpriteCache *sc, SpriteID id, SpriteType sprite_ty
 
 
 /** Map from sprite numbers to position in the GRF file. */
-static std::map<uint32, size_t> _grf_sprite_offsets;
+static btree::btree_map<uint32, size_t> _grf_sprite_offsets;
 
 /**
  * Get the file offset for a specific sprite in the sprite section of a GRF.
@@ -485,7 +487,8 @@ static std::map<uint32, size_t> _grf_sprite_offsets;
  */
 size_t GetGRFSpriteOffset(uint32 id)
 {
-	return _grf_sprite_offsets.find(id) != _grf_sprite_offsets.end() ? _grf_sprite_offsets[id] : SIZE_MAX;
+	auto iter = _grf_sprite_offsets.find(id);
+	return iter != _grf_sprite_offsets.end() ? iter->second : SIZE_MAX;
 }
 
 /**
diff --git a/src/terraform_cmd.cpp b/src/terraform_cmd.cpp
index aad9822822..1e9888e489 100644
--- a/src/terraform_cmd.cpp
+++ b/src/terraform_cmd.cpp
@@ -21,15 +21,15 @@
 
 #include "table/strings.h"
 
-#include <map>
-#include <set>
+#include "3rdparty/cpp-btree/btree_set.h"
+#include "3rdparty/cpp-btree/btree_map.h"
 
 #include "safeguards.h"
 
 /** Set of tiles. */
-typedef std::set<TileIndex> TileIndexSet;
+typedef btree::btree_set<TileIndex> TileIndexSet;
 /** Mapping of tiles to their height. */
-typedef std::map<TileIndex, int> TileIndexToHeightMap;
+typedef btree::btree_map<TileIndex, int> TileIndexToHeightMap;
 
 /** State of the terraforming. */
 struct TerraformerState {
diff --git a/src/tracerestrict.h b/src/tracerestrict.h
index ab41f3bacb..604269d1e5 100644
--- a/src/tracerestrict.h
+++ b/src/tracerestrict.h
@@ -18,7 +18,7 @@
 #include "rail_map.h"
 #include "tile_type.h"
 #include "group_type.h"
-#include <map>
+#include "3rdparty/cpp-btree/btree_map.h"
 #include <vector>
 
 struct Train;
@@ -50,7 +50,7 @@ struct TraceRestrictMappingItem {
 			: program_id(program_id_) { }
 };
 
-typedef std::map<TraceRestrictRefId, TraceRestrictMappingItem> TraceRestrictMapping;
+typedef btree::btree_map<TraceRestrictRefId, TraceRestrictMappingItem> TraceRestrictMapping;
 
 /** The actual mapping from TraceRestrictRefId to TraceRestrictProgramID. */
 extern TraceRestrictMapping _tracerestrictprogram_mapping;
diff --git a/src/vehicle.cpp b/src/vehicle.cpp
index 9634f04579..e6900e034e 100644
--- a/src/vehicle.cpp
+++ b/src/vehicle.cpp
@@ -57,6 +57,7 @@
 #include "tbtr_template_vehicle_func.h"
 #include "string_func.h"
 #include "scope_info.h"
+#include "3rdparty/cpp-btree/btree_set.h"
 
 #include "table/strings.h"
 
@@ -75,7 +76,7 @@ uint16 _returned_mail_refit_capacity; ///< Stores the mail capacity after a refi
 VehiclePool _vehicle_pool("Vehicle");
 INSTANTIATE_POOL_METHODS(Vehicle)
 
-static std::set<Vehicle *> _vehicles_to_pay_repair;
+static btree::btree_set<Vehicle *> _vehicles_to_pay_repair;
 
 /**
  * Determine shared bounds of all sprites.