diff --git a/src/models.rs b/src/models.rs
index 3858d7f..0be5d18 100644
--- a/src/models.rs
+++ b/src/models.rs
@@ -1,4 +1,5 @@
 pub mod battle_results;
 pub mod battle_results_dat;
 pub mod data;
+pub mod map_id;
 pub mod meta;
diff --git a/src/models/battle_results.rs b/src/models/battle_results.rs
index a56c73a..a3f016f 100644
--- a/src/models/battle_results.rs
+++ b/src/models/battle_results.rs
@@ -21,6 +21,15 @@ impl BattleResults {
 /// TODO: 150[0].21[0].8[0].801[0].unsigned is arena end time.
 #[derive(Message, Serialize)]
 pub struct BattleResults {
+    /// The two least-significant bytes is map ID.
+    ///
+    /// The 3rd byte is probably a game mode:
+    ///
+    /// - `0x0xxxx` is «encounter»
+    /// - `0x1xxxx` flag is «supremacy»
+    #[prost(uint32, tag = "1")]
+    pub mode_map_id: u32,
+
     /// Battle timestamp.
     #[prost(int64, tag = "2")]
     pub timestamp_secs: i64,
@@ -83,7 +92,6 @@ pub struct PlayerInfo {
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, Enumeration, Serialize)]
-#[repr(i32)]
 pub enum TeamNumber {
     One = 1,
     Two = 2,
diff --git a/src/models/map_id.rs b/src/models/map_id.rs
new file mode 100644
index 0000000..ac8d84e
--- /dev/null
+++ b/src/models/map_id.rs
@@ -0,0 +1,31 @@
+use prost::Enumeration;
+use serde::{Deserialize, Serialize};
+use serde_with::rust::deserialize_ignore_any;
+
+#[derive(Debug, Deserialize, Serialize, Enumeration)]
+#[serde(untagged)]
+pub enum MapId {
+    DesertSands = 2,
+    Middleburg = 3,
+    Copperfield = 4,
+    Mines = 6,
+    DeadRail = 7,
+    FortDespair = 8,
+    Himmelsdorf = 9,
+    OasisPalms = 11,
+    Molendijk = 14,
+    PortBay = 15,
+    Castilla = 20,
+    Canal = 21,
+    YamatoHarbor = 25,
+    Canyon = 27,
+    MayanRuins = 30,
+    NavalFrontier = 35,
+    Alpenstadt = 38,
+    NewBay = 40,
+    Normandy = 42,
+
+    /// Default value for Protocol Buffers and fallback value for Serde.
+    #[serde(deserialize_with = "deserialize_ignore_any")]
+    Undefined = 0,
+}
diff --git a/src/models/meta.rs b/src/models/meta.rs
index ac8a236..2bb4a20 100644
--- a/src/models/meta.rs
+++ b/src/models/meta.rs
@@ -5,6 +5,7 @@ use std::io::Read;
 
 use serde::Deserialize;
 
+use crate::models::map_id::MapId;
 use crate::result::Result;
 
 /// The model for `meta.json`.
@@ -21,6 +22,9 @@ pub struct Meta {
 
     #[serde(rename = "vehicleCompDescriptor")]
     pub tank_id: u16,
+
+    #[serde(rename = "mapId")]
+    pub map_id: MapId,
 }
 
 impl Meta {
diff --git a/tests/meta.rs b/tests/meta.rs
index 92b8667..7d9ddeb 100644
--- a/tests/meta.rs
+++ b/tests/meta.rs
@@ -14,6 +14,7 @@ fn meta_ok() -> Result<()> {
     assert_eq!(meta.arena_unique_id, "1661909200500084");
     assert_eq!(meta.battle_duration_secs, 164.08485);
     assert_eq!(meta.tank_id, 26657);
+    // TODO: assert_eq!(meta.map_id);
 
     Ok(())
 }