diff --git a/ImperatorToCK3/CK3/Provinces/ProvinceCollection.cs b/ImperatorToCK3/CK3/Provinces/ProvinceCollection.cs
index 817bab523..5ea4e6eb0 100644
--- a/ImperatorToCK3/CK3/Provinces/ProvinceCollection.cs
+++ b/ImperatorToCK3/CK3/Provinces/ProvinceCollection.cs
@@ -159,7 +159,13 @@ public void LoadPrehistory() {
 		var parser = new Parser();
 		parser.RegisterRegex(CommonRegexes.Integer, (reader, provIdStr) => {
 			var provId = ulong.Parse(provIdStr);
-			this[provId].UpdateHistory(reader);
+			
+			if (TryGetValue(provId, out var province)) {
+				province.UpdateHistory(reader);
+			} else {
+				Logger.Warn($"Province {provId} referenced in prehistory not found!");
+				ParserHelpers.IgnoreItem(reader);
+			}
 		});
 		parser.IgnoreAndLogUnregisteredItems();
 		parser.ParseFile(prehistoryPath);
diff --git a/ImperatorToCK3/CommonUtils/Map/MapData.cs b/ImperatorToCK3/CommonUtils/Map/MapData.cs
index c148ab39b..9bc83a846 100644
--- a/ImperatorToCK3/CommonUtils/Map/MapData.cs
+++ b/ImperatorToCK3/CommonUtils/Map/MapData.cs
@@ -493,21 +493,37 @@ private void DetermineMapEdgeProvinces(ModFilesystem modFS) {
 		for (var y = 0; y < height; ++y) {
 			// Get left edge color.
 			var color = GetPixelColor(new Point(0, y), mapPng);
-			mapEdgeProvinces.Add(ProvinceDefinitions.ColorToProvinceDict[color]);
+			if (ProvinceDefinitions.ColorToProvinceDict.TryGetValue(color, out var provinceId)) {
+				mapEdgeProvinces.Add(provinceId);
+			} else {
+				Logger.Warn($"Province not found for color {color}!");
+			}
 
 			// Get right edge color.
 			color = GetPixelColor(new Point(width - 1, y), mapPng);
-			mapEdgeProvinces.Add(ProvinceDefinitions.ColorToProvinceDict[color]);
+			if (ProvinceDefinitions.ColorToProvinceDict.TryGetValue(color, out provinceId)) {
+				mapEdgeProvinces.Add(provinceId);
+			} else {
+				Logger.Warn($"Province not found for color {color}!");
+			}
 		}
 
 		for (var x = 0; x < width; ++x) {
 			// Get top edge color.
 			var color = GetPixelColor(new Point(x, 0), mapPng);
-			mapEdgeProvinces.Add(ProvinceDefinitions.ColorToProvinceDict[color]);
+			if (ProvinceDefinitions.ColorToProvinceDict.TryGetValue(color, out var provinceId)) {
+				mapEdgeProvinces.Add(provinceId);
+			} else {
+				Logger.Warn($"Province not found for color {color}!");
+			}
 
 			// Get bottom edge color.
 			color = GetPixelColor(new Point(x, height - 1), mapPng);
-			mapEdgeProvinces.Add(ProvinceDefinitions.ColorToProvinceDict[color]);
+			if (ProvinceDefinitions.ColorToProvinceDict.TryGetValue(color, out provinceId)) {
+				mapEdgeProvinces.Add(provinceId);
+			} else {
+				Logger.Warn($"Province not found for color {color}!");
+			}
 		}
 	}
 }
\ No newline at end of file