diff --git a/distribution/changelog.txt b/distribution/changelog.txt
index 05f6ae163e..788bd70aea 100644
--- a/distribution/changelog.txt
+++ b/distribution/changelog.txt
@@ -1,6 +1,7 @@
 0.3.3+ (in development)
 ------------------------------------------------------------------------
 - Feature: [#14071] “Vandals stopped” statistic for security guards.
+- Fix: [#11829] Visual glitches and crashes when using RCT1 assets from mismatched or corrupt CSG1.DAT and CSG1i.DAT files.
 - Fix: [#13894] Block brakes do not animate.
 
 0.3.3 (2021-03-13)
diff --git a/src/openrct2/config/Config.cpp b/src/openrct2/config/Config.cpp
index 06007c8c19..a1873c0ccf 100644
--- a/src/openrct2/config/Config.cpp
+++ b/src/openrct2/config/Config.cpp
@@ -1000,7 +1000,7 @@ bool RCT1DataPresentAtLocation(const utf8* path)
 
 bool CsgIsUsable(const rct_gx& csg)
 {
-    return csg.header.num_entries == RCT1_NUM_LL_CSG_ENTRIES;
+    return csg.header.total_size == RCT1_LL_CSG1_DAT_FILE_SIZE && csg.header.num_entries == RCT1_NUM_LL_CSG_ENTRIES;
 }
 
 bool CsgAtLocationIsUsable(const utf8* path)
diff --git a/src/openrct2/rct1/RCT1.h b/src/openrct2/rct1/RCT1.h
index 3f3c951144..94d3e916f7 100644
--- a/src/openrct2/rct1/RCT1.h
+++ b/src/openrct2/rct1/RCT1.h
@@ -29,6 +29,7 @@ constexpr const uint16_t RCT1_MAX_ANIMATED_OBJECTS = 1000;
 constexpr const uint8_t RCT1_MAX_BANNERS = 100;
 constexpr int32_t RCT1_COORDS_Z_STEP = 4;
 constexpr const uint32_t RCT1_NUM_LL_CSG_ENTRIES = 69917;
+constexpr const uint32_t RCT1_LL_CSG1_DAT_FILE_SIZE = 41402869;
 
 struct ParkLoadResult;