diff --git a/src/deh_soc.c b/src/deh_soc.c
index 150d954dd..0352fc710 100644
--- a/src/deh_soc.c
+++ b/src/deh_soc.c
@@ -1079,11 +1079,6 @@ void readlevelheader(MYFILE *f, char * name)
 
 	const INT32 num = G_MapNumber(name);
 
-	if (num >= NUMMAPS)
-	{
-		I_Error("Too many maps!");
-	}
-
 	if (num >= nummapheaders)
 	{
 		P_AllocMapHeader((INT16)(num));
diff --git a/src/doomdata.h b/src/doomdata.h
index a8a0e387e..f08e61e6a 100644
--- a/src/doomdata.h
+++ b/src/doomdata.h
@@ -289,8 +289,6 @@ struct mapthing_t
 
 #define ZSHIFT 4
 
-#define NUMMAPS 1035
-
 /* slope thing types */
 enum
 {
diff --git a/src/doomstat.h b/src/doomstat.h
index b43acf77b..ad12065b1 100644
--- a/src/doomstat.h
+++ b/src/doomstat.h
@@ -453,8 +453,8 @@ struct mapheader_t
 #define LF2_NOTIMEATTACK  (1<<2) ///< Hide this map in Time Attack modes
 #define LF2_VISITNEEDED   (1<<3) ///< Not available in Time Attack modes until you visit the level
 
-extern mapheader_t* mapheaderinfo[NUMMAPS];
-extern INT32 nummapheaders,basenummapheaders;
+extern mapheader_t** mapheaderinfo;
+extern INT32 nummapheaders, basenummapheaders, mapallocsize;
 
 #define MAXMAPLUMPNAME 64 // includes \0, for cleaner savedata
 
diff --git a/src/g_game.c b/src/g_game.c
index 05ed3af40..b7f1e7613 100644
--- a/src/g_game.c
+++ b/src/g_game.c
@@ -182,8 +182,8 @@ UINT8 skipstats;
 struct quake quake;
 
 // Map Header Information
-mapheader_t* mapheaderinfo[NUMMAPS] = {NULL};
-INT32 nummapheaders = 0;
+mapheader_t** mapheaderinfo = {NULL};
+INT32 nummapheaders, mapallocsize = 0;
 INT32 basenummapheaders = 0;
 
 // Kart cup definitions
diff --git a/src/p_setup.c b/src/p_setup.c
index bdfc513d5..348ceb675 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -462,9 +462,43 @@ static void P_ClearSingleMapHeaderInfo(INT16 i)
   */
 void P_AllocMapHeader(INT16 i)
 {
+	if (i > nummapheaders)
+		I_Error("P_AllocMapHeader: Called on %d, should be %d", i, nummapheaders);
+
+	if (i >= NEXTMAP_SPECIAL)
+	{
+		I_Error("P_AllocMapHeader: Too many maps!");
+	}
+
+	if (i >= mapallocsize)
+	{
+		if (!mapallocsize)
+		{
+			mapallocsize = 16;
+		}
+		else
+		{
+			mapallocsize *= 2;
+		}
+
+		mapheaderinfo = Z_ReallocAlign(
+			(void*) mapheaderinfo,
+			sizeof(mapheader_t*) * mapallocsize,
+			PU_STATIC,
+			NULL,
+			sizeof(mapheader_t*) * 8
+		);
+
+		if (!mapheaderinfo)
+			I_Error("P_AllocMapHeader: Not enough memory to realloc mapheaderinfo (size %d)", mapallocsize);
+	}
+
 	if (!mapheaderinfo[i])
 	{
 		mapheaderinfo[i] = Z_Malloc(sizeof(mapheader_t), PU_STATIC, NULL);
+		if (!mapheaderinfo[i])
+			I_Error("P_AllocMapHeader: Not enough memory to allocate new mapheader");
+
 		mapheaderinfo[i]->lumpnum = LUMPERROR;
 		mapheaderinfo[i]->lumpname = NULL;
 		mapheaderinfo[i]->thumbnailPic = NULL;