diff --git a/src/openvic-simulation/map/ProvinceInstance.cpp b/src/openvic-simulation/map/ProvinceInstance.cpp
index c28da842..e04c8145 100644
--- a/src/openvic-simulation/map/ProvinceInstance.cpp
+++ b/src/openvic-simulation/map/ProvinceInstance.cpp
@@ -180,16 +180,6 @@ void ProvinceInstance::_add_pop(Pop&& pop) {
 	pops.insert(std::move(pop));
 }
 
-bool ProvinceInstance::add_pop(Pop&& pop) {
-	if (!province_definition.is_water()) {
-		_add_pop(std::move(pop));
-		return true;
-	} else {
-		spdlog::error_s("Trying to add pop to water province {}", *this);
-		return false;
-	}
-}
-
 bool ProvinceInstance::add_pop_vec(
 	std::span<const PopBase> pop_vec,
 	PopDeps const& pop_deps
@@ -200,7 +190,8 @@ bool ProvinceInstance::add_pop_vec(
 			_add_pop(Pop {
 				pop,
 				get_supporter_equivalents_by_ideology().get_keys(),
-				pop_deps
+				pop_deps,
+				++last_pop_id
 			});
 		}
 		return true;
diff --git a/src/openvic-simulation/map/ProvinceInstance.hpp b/src/openvic-simulation/map/ProvinceInstance.hpp
index 9d68aaad..e39f0603 100644
--- a/src/openvic-simulation/map/ProvinceInstance.hpp
+++ b/src/openvic-simulation/map/ProvinceInstance.hpp
@@ -5,16 +5,17 @@
 #include "openvic-simulation/core/portable/ForwardableSpan.hpp"
 #include "openvic-simulation/economy/BuildingInstance.hpp"
 #include "openvic-simulation/economy/production/ResourceGatheringOperation.hpp"
+#include "openvic-simulation/map/LifeRating.hpp"
 #include "openvic-simulation/military/UnitBranchedGetterMacro.hpp"
 #include "openvic-simulation/modifier/ModifierSum.hpp"
 #include "openvic-simulation/population/Pop.hpp"
+#include "openvic-simulation/population/PopIdInProvince.hpp"
 #include "openvic-simulation/population/PopsAggregate.hpp"
 #include "openvic-simulation/types/ColonyStatus.hpp"
 #include "openvic-simulation/types/FlagStrings.hpp"
 #include "openvic-simulation/types/HasIdentifier.hpp"
 #include "openvic-simulation/types/HasIndex.hpp"
 #include "openvic-simulation/types/OrderedContainers.hpp"
-#include "openvic-simulation/map/LifeRating.hpp"
 #include "openvic-simulation/types/FixedVector.hpp"
 #include "openvic-simulation/types/TypedIndices.hpp"
 #include "openvic-simulation/types/TypedSpan.hpp"
@@ -115,6 +116,7 @@ namespace OpenVic {
 		OV_UNIT_BRANCHED_GETTER_CONST(get_unit_instance_groups, armies, navies);
 
 	private:
+		pop_id_in_province_t last_pop_id{0};
 		memory::colony<Pop> PROPERTY(pops); // TODO - replace with a more easily vectorisable container?		
 		void _add_pop(Pop&& pop);
 		void _update_pops(MilitaryDefines const& military_defines);
@@ -168,7 +170,6 @@ namespace OpenVic {
 
 		bool expand_building(const province_building_index_t index);
 
-		bool add_pop(Pop&& pop);
 		bool add_pop_vec(
 			std::span<const PopBase> pop_vec,
 			PopDeps const& pop_deps
diff --git a/src/openvic-simulation/population/Pop.cpp b/src/openvic-simulation/population/Pop.cpp
index 99842cd7..aa475e9f 100644
--- a/src/openvic-simulation/population/Pop.cpp
+++ b/src/openvic-simulation/population/Pop.cpp
@@ -15,7 +15,8 @@
 #include "openvic-simulation/country/CountryParty.hpp"
 #include "openvic-simulation/country/CountryDefinition.hpp"
 #include "openvic-simulation/country/CountryInstance.hpp"
-#include "openvic-simulation/defines/Define.hpp"
+#include "openvic-simulation/defines/MilitaryDefines.hpp"
+#include "openvic-simulation/defines/PopsDefines.hpp"
 #include "openvic-simulation/economy/GoodDefinition.hpp"
 #include "openvic-simulation/economy/GoodInstance.hpp"
 #include "openvic-simulation/economy/production/ArtisanalProducer.hpp"
@@ -54,9 +55,11 @@ PopBase::PopBase(
 Pop::Pop(
 	PopBase const& pop_base,
 	decltype(supporter_equivalents_by_ideology)::keys_span_type ideology_keys,
-	PopDeps const& pop_deps
+	PopDeps const& pop_deps,
+	const pop_id_in_province_t new_id_in_province
 )
   : PopBase { pop_base },
+  	id_in_province { new_id_in_province },
 	market_instance { pop_deps.market_instance },
 	artisanal_producer_optional {
 		type->is_artisan
diff --git a/src/openvic-simulation/population/Pop.hpp b/src/openvic-simulation/population/Pop.hpp
index 47391ef1..cc01ebf7 100644
--- a/src/openvic-simulation/population/Pop.hpp
+++ b/src/openvic-simulation/population/Pop.hpp
@@ -4,12 +4,13 @@
 
 #include "openvic-simulation/core/portable/ForwardableSpan.hpp"
 #include "openvic-simulation/economy/production/ArtisanalProducer.hpp"
+#include "openvic-simulation/population/PopIdInProvince.hpp"
 #include "openvic-simulation/population/PopNeedsMacro.hpp"
+#include "openvic-simulation/population/PopSize.hpp"
 #include "openvic-simulation/types/fixed_point/Atomic.hpp"
 #include "openvic-simulation/types/fixed_point/FixedPoint.hpp"
 #include "openvic-simulation/types/fixed_point/FixedPointMap.hpp"
 #include "openvic-simulation/types/IndexedFlatMap.hpp"
-#include "openvic-simulation/population/PopSize.hpp"
 #include "openvic-simulation/types/UnitBranchType.hpp"
 #include "openvic-simulation/utility/Containers.hpp"
 
@@ -89,6 +90,9 @@ namespace OpenVic {
 
 		static constexpr pop_size_t MAX_SIZE = std::numeric_limits<type_safe::underlying_type<pop_size_t>>::max();
 
+	public:
+		const pop_id_in_province_t id_in_province;
+
 	private:
 		MarketInstance& market_instance;
 		std::optional<ArtisanalProducer> artisanal_producer_optional;
@@ -163,7 +167,8 @@ namespace OpenVic {
 		Pop(
 			PopBase const& pop_base,
 			decltype(supporter_equivalents_by_ideology)::keys_span_type ideology_keys,
-			PopDeps const& pop_deps
+			PopDeps const& pop_deps,
+			const pop_id_in_province_t new_id_in_province
 		);
 
 		memory::string get_pop_context_text() const;
diff --git a/src/openvic-simulation/population/PopIdInProvince.hpp b/src/openvic-simulation/population/PopIdInProvince.hpp
new file mode 100644
index 00000000..2759b93d
--- /dev/null
+++ b/src/openvic-simulation/population/PopIdInProvince.hpp
@@ -0,0 +1,27 @@
+#pragma once
+
+#include <cstddef>
+
+#include <fmt/base.h>
+#include <fmt/format.h>
+
+#include <type_safe/strong_typedef.hpp>
+
+namespace OpenVic {
+	struct pop_id_in_province_t : type_safe::strong_typedef<pop_id_in_province_t, std::size_t>,
+		type_safe::strong_typedef_op::equality_comparison<pop_id_in_province_t>,
+		type_safe::strong_typedef_op::relational_comparison<pop_id_in_province_t>,
+		type_safe::strong_typedef_op::integer_arithmetic<pop_id_in_province_t> {
+		using strong_typedef::strong_typedef;
+	};
+}
+namespace std {
+	template <>
+	struct hash<OpenVic::pop_id_in_province_t> : type_safe::hashable<OpenVic::pop_id_in_province_t> {};
+}
+template<>
+struct fmt::formatter<OpenVic::pop_id_in_province_t> : fmt::formatter<std::size_t> {
+	fmt::format_context::iterator format(OpenVic::pop_id_in_province_t const& value, fmt::format_context& ctx) const {
+		return fmt::formatter<std::size_t>::format(type_safe::get(value), ctx);
+	}
+};
\ No newline at end of file