diff --git a/src/saveload/extended_ver_sl.cpp b/src/saveload/extended_ver_sl.cpp
index 1f4dae220f..1a9779aa5a 100644
--- a/src/saveload/extended_ver_sl.cpp
+++ b/src/saveload/extended_ver_sl.cpp
@@ -183,6 +183,7 @@ const SlxiSubChunkInfo _sl_xv_sub_chunk_infos[] = {
 	{ XSLFI_LINKGRAPH_SPARSE_EDGES, XSCF_NULL,                1,   1, "linkgraph_sparse_edges",    nullptr, nullptr, nullptr        },
 	{ XSLFI_AUX_TILE_LOOP,          XSCF_NULL,                1,   1, "aux_tile_loop",             nullptr, nullptr, nullptr        },
 	{ XSLFI_NEWGRF_ENTITY_EXTRA,    XSCF_NULL,                1,   1, "newgrf_entity_extra",       nullptr, nullptr, nullptr        },
+	{ XSLFI_TNNC_CHUNK,             XSCF_IGNORABLE_ALL,       1,   1, "tnnc_chunk",                nullptr, nullptr, "TNNC"         },
 	{ XSLFI_SCRIPT_INT64,           XSCF_NULL,                1,   1, "script_int64",              nullptr, nullptr, nullptr        },
 	{ XSLFI_U64_TICK_COUNTER,       XSCF_NULL,                1,   1, "u64_tick_counter",          nullptr, nullptr, nullptr        },
 	{ XSLFI_LINKGRAPH_TRAVEL_TIME,  XSCF_NULL,                1,   1, "linkgraph_travel_time",     nullptr, nullptr, nullptr        },
diff --git a/src/saveload/extended_ver_sl.h b/src/saveload/extended_ver_sl.h
index 0694619db0..2638190002 100644
--- a/src/saveload/extended_ver_sl.h
+++ b/src/saveload/extended_ver_sl.h
@@ -134,6 +134,7 @@ enum SlXvFeatureIndex {
 	XSLFI_LINKGRAPH_SPARSE_EDGES,                 ///< Link graph edge matrix is stored in sparse format, and saved in order
 	XSLFI_AUX_TILE_LOOP,                          ///< Auxiliary tile loop
 	XSLFI_NEWGRF_ENTITY_EXTRA,                    ///< NewGRF entity mappings are 16 bit
+	XSLFI_TNNC_CHUNK,                             ///< TNNC chunk
 
 	XSLFI_SCRIPT_INT64,                           ///< See: SLV_SCRIPT_INT64
 	XSLFI_U64_TICK_COUNTER,                       ///< See: SLV_U64_TICK_COUNTER
diff --git a/src/saveload/saveload.cpp b/src/saveload/saveload.cpp
index b208ab43d9..ad301ff945 100644
--- a/src/saveload/saveload.cpp
+++ b/src/saveload/saveload.cpp
@@ -3437,8 +3437,10 @@ static SaveOrLoadResult DoLoad(LoadFilter *reader, bool load_check)
 
 	SlXvResetState();
 	SlResetVENC();
+	SlResetTNNC();
 	auto guard = scope_guard([&]() {
 		SlResetVENC();
+		SlResetTNNC();
 	});
 
 	uint32 hdr[2];
diff --git a/src/saveload/saveload.h b/src/saveload/saveload.h
index 512ba0bcd9..26f55f9758 100644
--- a/src/saveload/saveload.h
+++ b/src/saveload/saveload.h
@@ -750,6 +750,8 @@ bool SaveloadCrashWithMissingNewGRFs();
 void SlResetVENC();
 void SlProcessVENC();
 
+void SlResetTNNC();
+
 extern std::string _savegame_format;
 extern bool _do_autosave;
 
diff --git a/src/saveload/town_sl.cpp b/src/saveload/town_sl.cpp
index 66a72cf2ab..a2ffaf1347 100644
--- a/src/saveload/town_sl.cpp
+++ b/src/saveload/town_sl.cpp
@@ -13,12 +13,15 @@
 #include "../landscape.h"
 #include "../subsidy_func.h"
 #include "../strings_func.h"
+#include "../network/network.h"
 
 #include "saveload.h"
 #include "newgrf_sl.h"
 
 #include "../safeguards.h"
 
+static bool _town_zone_radii_no_update = false;
+
 HouseID SLGetCleanHouseType(TileIndex t, bool old_map_position)
 {
 	if (old_map_position && SlXvIsFeatureMissing(XSLFI_MORE_HOUSES)) {
@@ -54,9 +57,11 @@ void RebuildTownCaches(bool cargo_update_required, bool old_map_position)
 		if (GetHouseNorthPart(house_id) == 0) town->cache.num_houses++;
 	}
 
-	/* Update the population and num_house dependent values */
-	for (Town *town : Town::Iterate()) {
-		UpdateTownRadius(town);
+	if (!_town_zone_radii_no_update) {
+		/* Update the population and num_house dependent values */
+		for (Town *town : Town::Iterate()) {
+			UpdateTownRadius(town);
+		}
 	}
 }
 
@@ -363,10 +368,55 @@ static void Ptrs_TOWN()
 	}
 }
 
+void SlResetTNNC()
+{
+	_town_zone_radii_no_update = false;
+}
+
+void Save_TNNC()
+{
+	if (!IsNetworkServerSave()) {
+		SlSetLength(0);
+		return;
+	}
+
+	SlSetLength(4 + (Town::GetNumItems() * (1 + lengthof(TownCache::squared_town_zone_radius)) * 4));
+
+	SlWriteUint32(Town::GetNumItems());
+
+	for (const Town *t : Town::Iterate()) {
+		SlWriteUint32(t->index);
+		for (uint i = 0; i < lengthof(TownCache::squared_town_zone_radius); i++) {
+			SlWriteUint32(t->cache.squared_town_zone_radius[i]);
+		}
+	}
+}
+
+void Load_TNNC()
+{
+	if (SlGetFieldLength() == 0) return;
+
+	if (!_networking || _network_server) {
+		SlSkipBytes(SlGetFieldLength());
+		return;
+	}
+
+	_town_zone_radii_no_update = true;
+
+	const uint32 count = SlReadUint32();
+	for (uint32 idx = 0; idx < count; idx++) {
+		Town *t = Town::Get(SlReadUint32());
+		for (uint i = 0; i < lengthof(TownCache::squared_town_zone_radius); i++) {
+			t->cache.squared_town_zone_radius[i] = SlReadUint32();
+		}
+	}
+}
+
 /** Chunk handler for towns. */
 static const ChunkHandler town_chunk_handlers[] = {
 	{ 'HIDS', Save_HIDS, Load_HIDS, nullptr,   nullptr, CH_ARRAY },
 	{ 'CITY', Save_TOWN, Load_TOWN, Ptrs_TOWN, nullptr, CH_ARRAY },
+	{ 'TNNC', Save_TNNC, Load_TNNC, nullptr,   nullptr, CH_RIFF  },
 };
 
 extern const ChunkHandlerTable _town_chunk_handlers(town_chunk_handlers);