diff --git a/src/generated/resources/data/minecraft/tags/worldgen/biome/is_mountain.json b/src/generated/resources/data/forge/tags/worldgen/biome/is_mountain.json
similarity index 100%
rename from src/generated/resources/data/minecraft/tags/worldgen/biome/is_mountain.json
rename to src/generated/resources/data/forge/tags/worldgen/biome/is_mountain.json
diff --git a/src/main/java/net/minecraftforge/common/Tags.java b/src/main/java/net/minecraftforge/common/Tags.java
index 18a57fef28..3d24b16bf9 100644
--- a/src/main/java/net/minecraftforge/common/Tags.java
+++ b/src/main/java/net/minecraftforge/common/Tags.java
@@ -470,6 +470,7 @@ public class Tags
 
         public static final TagKey<Biome> IS_PEAK = tag("is_peak");
         public static final TagKey<Biome> IS_SLOPE = tag("is_slope");
+        public static final TagKey<Biome> IS_MOUNTAIN = tag("is_mountain");
 
         public static final TagKey<Biome> IS_OVERWORLD = tag("is_overworld");
         public static final TagKey<Biome> IS_END = tag("is_end");
diff --git a/src/main/java/net/minecraftforge/common/data/ForgeBiomeTagsProvider.java b/src/main/java/net/minecraftforge/common/data/ForgeBiomeTagsProvider.java
index fd901290a0..4fd11c655f 100644
--- a/src/main/java/net/minecraftforge/common/data/ForgeBiomeTagsProvider.java
+++ b/src/main/java/net/minecraftforge/common/data/ForgeBiomeTagsProvider.java
@@ -88,7 +88,7 @@ public final class ForgeBiomeTagsProvider extends BiomeTagsProvider
         tag(Biomes.BASALT_DELTAS, Tags.Biomes.IS_HOT, Tags.Biomes.IS_HOT_NETHER, Tags.Biomes.IS_DRY, Tags.Biomes.IS_DRY_NETHER);
 
         tag(Tags.Biomes.IS_WATER).addTag(BiomeTags.IS_OCEAN).addTag(BiomeTags.IS_RIVER);
-        tag(BiomeTags.IS_MOUNTAIN).addTag(Tags.Biomes.IS_PEAK).addTag(Tags.Biomes.IS_SLOPE);
+        tag(Tags.Biomes.IS_MOUNTAIN).addTag(Tags.Biomes.IS_PEAK).addTag(Tags.Biomes.IS_SLOPE);
     }
 
     @SafeVarargs