diff --git a/bitchat/Services/GeohashChatActivityTracker.swift b/bitchat/Services/GeohashChatActivityTracker.swift
index def9d59f..c3d3cdcd 100644
--- a/bitchat/Services/GeohashChatActivityTracker.swift
+++ b/bitchat/Services/GeohashChatActivityTracker.swift
@@ -41,6 +41,12 @@ final class GeohashChatActivityTracker: ObservableObject {
     private var lastMessages: [String: GeohashChatPreview] = [:]
     private let now: () -> Date
 
+    #if DEBUG
+    /// Number of distinct geohashes currently held in memory; exposed only
+    /// for regression tests verifying stale entries get evicted.
+    var _trackedGeohashCountForTesting: Int { messageTimes.count }
+    #endif
+
     init(
         window: TimeInterval = TransportConfig.uiGeohashChatActivityWindowSeconds,
         now: @escaping () -> Date = { Date() }
@@ -68,6 +74,15 @@ final class GeohashChatActivityTracker: ObservableObject {
         } else {
             lastMessages[gh] = GeohashChatPreview(senderName: senderName, content: content, timestamp: clamped)
         }
+
+        // A geohash's timestamp array only ever gets pruned down to empty —
+        // its dictionary entry (and the paired lastMessages entry) is never
+        // dropped, so roaming across many regions over a long session leaks
+        // one entry per distinct geohash ever observed. Sweep other geohashes
+        // here so activity that has fully aged out gets evicted instead of
+        // sitting in memory for the rest of the process's lifetime.
+        pruneStaleGeohashes(except: gh)
+
         objectWillChange.send()
     }
 
@@ -113,4 +128,15 @@ final class GeohashChatActivityTracker: ObservableObject {
         let cutoff = now().addingTimeInterval(-window)
         return times.filter { $0 >= cutoff }
     }
+
+    /// Drops any tracked geohash (other than `keep`) whose messages have all
+    /// aged out of the window, so the maps stay bounded to recently-active
+    /// geohashes instead of growing for the life of the process.
+    private func pruneStaleGeohashes(except keep: String) {
+        for gh in Array(messageTimes.keys) where gh != keep {
+            guard prune(messageTimes[gh] ?? []).isEmpty else { continue }
+            messageTimes.removeValue(forKey: gh)
+            lastMessages.removeValue(forKey: gh)
+        }
+    }
 }
diff --git a/bitchatTests/Services/GeohashChatActivityTrackerTests.swift b/bitchatTests/Services/GeohashChatActivityTrackerTests.swift
index a9786b14..b9fe7570 100644
--- a/bitchatTests/Services/GeohashChatActivityTrackerTests.swift
+++ b/bitchatTests/Services/GeohashChatActivityTrackerTests.swift
@@ -110,4 +110,32 @@ struct GeohashChatActivityTrackerTests {
         #expect(tracker.messageCount(for: "9q8yy") == 0)
         #expect(tracker.mostActiveConversation(among: [channel("9q8yy", .city)]) == nil)
     }
+
+    @Test
+    func staleGeohashesAreEvictedNotJustEmptied() {
+        let (tracker, advance) = makeTracker(window: 900)
+        tracker.recordChatMessage(geohash: "9q8yy", senderName: "a#1111", content: "old region", timestamp: baseDate)
+        #expect(tracker._trackedGeohashCountForTesting == 1)
+
+        // Move well past the window, then record activity in a different
+        // geohash — this should sweep the now-stale "9q8yy" entry out of
+        // memory instead of leaving an empty-but-present dictionary entry.
+        advance(baseDate.addingTimeInterval(901))
+        tracker.recordChatMessage(geohash: "9r1zz", senderName: "b#2222", content: "new region", timestamp: baseDate.addingTimeInterval(901))
+
+        #expect(tracker._trackedGeohashCountForTesting == 1)
+        #expect(tracker.messageCount(for: "9q8yy") == 0)
+        #expect(tracker.messageCount(for: "9r1zz") == 1)
+    }
+
+    @Test
+    func activeGeohashSurvivesSweepEvenWhenMomentarilyEmpty() {
+        // The geohash currently being recorded to is exempt from the sweep,
+        // so recording its own first message never evicts itself.
+        let (tracker, _) = makeTracker(window: 900)
+        tracker.recordChatMessage(geohash: "9q8yy", senderName: "a#1111", content: "hi", timestamp: baseDate)
+
+        #expect(tracker._trackedGeohashCountForTesting == 1)
+        #expect(tracker.messageCount(for: "9q8yy") == 1)
+    }
 }