diff --git a/src/components/Map/MapView.jsx b/src/components/Map/MapView.jsx
index fd3806c..e8438c5 100644
--- a/src/components/Map/MapView.jsx
+++ b/src/components/Map/MapView.jsx
@@ -75,6 +75,7 @@ export default function MapView({
       markersRef,
       expandedElRef,
       onAutoWidenTimeFilter: (next) => setTimeFilter(next),
+      onSelectPost,
     });
 
   const [isCreating, setIsCreating] = useState(false);
diff --git a/src/components/Map/markerManager.js b/src/components/Map/markerManager.js
index c03e94e..bf1f0a3 100644
--- a/src/components/Map/markerManager.js
+++ b/src/components/Map/markerManager.js
@@ -433,7 +433,7 @@ export function createMarkerForPost(post, mapRef, markersRef, expandedElRef, the
     .setLngLat(lngLat)
     .addTo(map);
 
-  markersRef.current.push({ id: post.id, marker, el: root, post });
+  markersRef.current.push({ id: post.id, marker, el: root, post, type: "full" });
 
   root.addEventListener("click", (ev) => {
     ev.stopPropagation();
diff --git a/src/components/Map/usePostsEngine.js b/src/components/Map/usePostsEngine.js
index 8ec2fe2..4e9d005 100644
--- a/src/components/Map/usePostsEngine.js
+++ b/src/components/Map/usePostsEngine.js
@@ -81,6 +81,30 @@ function hasPostsInRadius(posts, centerLat, centerLon, radiusKm) {
   return false;
 }
 
+function filterByBounds(posts, map) {
+  if (!map || !Array.isArray(posts) || posts.length === 0) return posts || [];
+  let bounds;
+  try { bounds = map.getBounds(); } catch {}
+  if (!bounds) return posts;
+  const sw = bounds.getSouthWest();
+  const ne = bounds.getNorthEast();
+  if (!sw || !ne) return posts;
+
+  const padLat = Math.abs(ne.lat - sw.lat) * 0.12;
+  const padLon = Math.abs(ne.lng - sw.lng) * 0.12;
+  const minLat = sw.lat - padLat;
+  const maxLat = ne.lat + padLat;
+  const minLon = sw.lng - padLon;
+  const maxLon = ne.lng + padLon;
+
+  return posts.filter((p) => {
+    const coords = getCoords(p);
+    if (!coords) return false;
+    const [lon, lat] = coords;
+    return lat >= minLat && lat <= maxLat && lon >= minLon && lon <= maxLon;
+  });
+}
+
 export function usePostsEngine({
   mapRef,
   viewParams,
@@ -91,6 +115,7 @@ export function usePostsEngine({
   markersRef,
   expandedElRef,
   onAutoWidenTimeFilter,
+  onSelectPost,
   theme = "blue",
 }) {
   const allPostsRef = useRef([]);
@@ -98,6 +123,14 @@ export function usePostsEngine({
   const delayedFetchRef = useRef(null);
   const autoWidenRef = useRef(false);
   const [mapReady, setMapReady] = useState(false);
+  const clusterModeRef = useRef(false);
+
+  const CLUSTER_THRESHOLD = 140;
+  const SIMPLE_MARKER_LIMIT = 40;
+  const CLUSTER_SOURCE_ID = "sw-posts";
+  const CLUSTER_LAYER_ID = "sw-clusters";
+  const CLUSTER_COUNT_ID = "sw-cluster-count";
+  const UNCLUSTERED_ID = "sw-unclustered";
 
   useEffect(() => {
     if (mapReady) return;
@@ -116,6 +149,238 @@ export function usePostsEngine({
     };
   }, [mapReady, mapRef]);
 
+  const priorityOpts = {
+    maxFullCards: 12,
+    clusterRadius: 0.002,
+    minScoreForCard: 50,
+  };
+
+  const ensureClusterLayers = useCallback((map) => {
+    if (!map) return;
+    if (typeof map.isStyleLoaded === "function" && !map.isStyleLoaded()) return;
+    if (map.getSource(CLUSTER_SOURCE_ID)) return;
+
+    map.addSource(CLUSTER_SOURCE_ID, {
+      type: "geojson",
+      data: { type: "FeatureCollection", features: [] },
+      cluster: true,
+      clusterMaxZoom: 12,
+      clusterRadius: 46,
+    });
+
+    map.addLayer({
+      id: CLUSTER_LAYER_ID,
+      type: "circle",
+      source: CLUSTER_SOURCE_ID,
+      filter: ["has", "point_count"],
+      paint: {
+        "circle-color": [
+          "step",
+          ["get", "point_count"],
+          "#22d3ee",
+          30,
+          "#3b82f6",
+          100,
+          "#1d4ed8",
+        ],
+        "circle-radius": [
+          "step",
+          ["get", "point_count"],
+          16,
+          30,
+          22,
+          100,
+          28,
+        ],
+        "circle-opacity": 0.85,
+        "circle-stroke-color": "#e2e8f0",
+        "circle-stroke-width": 1.2,
+      },
+    });
+
+    map.addLayer({
+      id: CLUSTER_COUNT_ID,
+      type: "symbol",
+      source: CLUSTER_SOURCE_ID,
+      filter: ["has", "point_count"],
+      layout: {
+        "text-field": "{point_count_abbreviated}",
+        "text-size": 12,
+        "text-font": ["Open Sans Semibold", "Arial Unicode MS Bold"],
+      },
+      paint: {
+        "text-color": "#0b1220",
+      },
+    });
+
+    map.addLayer({
+      id: UNCLUSTERED_ID,
+      type: "circle",
+      source: CLUSTER_SOURCE_ID,
+      filter: ["!", ["has", "point_count"]],
+      paint: {
+        "circle-color": "#38bdf8",
+        "circle-radius": 6,
+        "circle-opacity": 0.9,
+        "circle-stroke-color": "#0b1220",
+        "circle-stroke-width": 1,
+      },
+    });
+
+    if (!map.__swClusterHandlers) {
+      map.__swClusterHandlers = true;
+
+      map.on("click", CLUSTER_LAYER_ID, (e) => {
+        const features = map.queryRenderedFeatures(e.point, { layers: [CLUSTER_LAYER_ID] });
+        const clusterFeature = features && features[0];
+        if (!clusterFeature) return;
+        const clusterId = clusterFeature.properties?.cluster_id;
+        const source = map.getSource(CLUSTER_SOURCE_ID);
+        if (!source || clusterId == null || !source.getClusterExpansionZoom) return;
+        source.getClusterExpansionZoom(clusterId, (err, zoom) => {
+          if (err) return;
+          map.easeTo({ center: clusterFeature.geometry.coordinates, zoom, duration: 520 });
+        });
+      });
+
+      map.on("click", UNCLUSTERED_ID, (e) => {
+        const f = e.features && e.features[0];
+        if (!f || !f.properties) return;
+        const raw = f.properties.post_json;
+        if (!raw) return;
+        let post = null;
+        try { post = JSON.parse(raw); } catch {}
+        if (post && typeof onSelectPost === "function") onSelectPost(post);
+      });
+
+      map.on("mouseenter", CLUSTER_LAYER_ID, () => {
+        map.getCanvas().style.cursor = "pointer";
+      });
+      map.on("mouseleave", CLUSTER_LAYER_ID, () => {
+        map.getCanvas().style.cursor = "";
+      });
+      map.on("mouseenter", UNCLUSTERED_ID, () => {
+        map.getCanvas().style.cursor = "pointer";
+      });
+      map.on("mouseleave", UNCLUSTERED_ID, () => {
+        map.getCanvas().style.cursor = "";
+      });
+    }
+  }, [onSelectPost]);
+
+  const setClusterVisibility = useCallback((map, visible) => {
+    if (!map) return;
+    const v = visible ? "visible" : "none";
+    if (map.getLayer(CLUSTER_LAYER_ID)) map.setLayoutProperty(CLUSTER_LAYER_ID, "visibility", v);
+    if (map.getLayer(CLUSTER_COUNT_ID)) map.setLayoutProperty(CLUSTER_COUNT_ID, "visibility", v);
+    if (map.getLayer(UNCLUSTERED_ID)) map.setLayoutProperty(UNCLUSTERED_ID, "visibility", v);
+  }, []);
+
+  const updateClusterData = useCallback((map, posts) => {
+    if (!map) return;
+    const src = map.getSource(CLUSTER_SOURCE_ID);
+    if (!src || !src.setData) return;
+    const features = [];
+    for (const p of posts || []) {
+      const coords = getCoords(p);
+      if (!coords) continue;
+      const [lon, lat] = coords;
+      const payload = {
+        id: getId(p),
+        title: p.title || p.Title || "",
+        snippet: p.snippet || "",
+        category: p.category || p.Category || "",
+        sub_category: p.sub_category || p.subCategory || "",
+        lat,
+        lon,
+        url: p.url || "",
+        source: p.source || "",
+        created_at: p.created_at || p.CreatedAt || p.createdAt || "",
+        published_at: p.published_at || "",
+        url_hash: p.url_hash || p.urlHash || "",
+      };
+      features.push({
+        type: "Feature",
+        geometry: { type: "Point", coordinates: [lon, lat] },
+        properties: {
+          id: payload.id || 0,
+          post_json: JSON.stringify(payload),
+        },
+      });
+    }
+    src.setData({ type: "FeatureCollection", features });
+  }, []);
+
+  const splitForClusters = useCallback(
+    (visible) => {
+      const map = mapRef.current;
+      if (!map) return { fullCardPosts: [], clusterPosts: visible || [] };
+      const center = map.getCenter();
+      const viewCenter = center ? { lng: center.lng, lat: center.lat } : null;
+      const { fullCardPosts, simpleMarkerPosts } = prioritizePosts(
+        visible || [],
+        viewCenter,
+        priorityOpts
+      );
+      return { fullCardPosts, clusterPosts: simpleMarkerPosts };
+    },
+    [mapRef, priorityOpts]
+  );
+
+  const syncPriorityMarkers = useCallback(
+    (fullList, simpleList) => {
+      const map = mapRef.current;
+      if (!map) return;
+      if (expandedElRef?.current) return;
+
+      const wanted = new Map();
+      for (const post of fullList || []) {
+        const id = getId(post);
+        if (id != null) wanted.set(id, { post, type: "full" });
+      }
+      for (const post of simpleList || []) {
+        const id = getId(post);
+        if (id != null && !wanted.has(id)) wanted.set(id, { post, type: "simple" });
+      }
+
+      const cur = markersRef.current || [];
+      const next = [];
+
+      for (const item of cur) {
+        const id = item?.id;
+        const want = id != null ? wanted.get(id) : null;
+        const haveType = item?.type || "full";
+        if (!want || haveType !== want.type) {
+          try {
+            const el = item?.el;
+            if (el) {
+              el.classList.add("sw-disappear");
+              el.style.pointerEvents = "none";
+            }
+          } catch {}
+          setTimeout(() => {
+            try { if (item?.el && item.el.__swUnmount) item.el.__swUnmount(); } catch {}
+            try { item?.marker?.remove?.(); } catch {}
+          }, 840);
+        } else {
+          next.push(item);
+        }
+      }
+
+      markersRef.current = next;
+      const have = new Set(next.map((x) => x.id));
+      for (const [id, entry] of wanted.entries()) {
+        if (have.has(id)) continue;
+        if (entry.type === "simple") {
+          createSimpleMarkerForPost(entry.post, mapRef, markersRef, expandedElRef, theme);
+        } else {
+          createMarkerForPost(entry.post, mapRef, markersRef, expandedElRef, theme);
+        }
+      }
+    },
+    [mapRef, markersRef, expandedElRef, theme]
+  );
+
   const [status, setStatus] = useState("");
   const [visiblePosts, setVisiblePosts] = useState([]);
   const [loadingPosts, setLoadingPosts] = useState(false);
@@ -220,7 +485,9 @@ export function usePostsEngine({
 
   const refreshVisibleAndMarkers = useCallback(
     (tf) => {
-      const v = computeVisible(tf);
+      const vAll = computeVisible(tf);
+      const map = mapRef.current;
+      const v = filterByBounds(vAll, map);
 
       // reduce wall blink: don't update if same ids
       setVisiblePosts((prev) => (sameIdList(prev, v) ? prev : v));
@@ -228,9 +495,27 @@ export function usePostsEngine({
       // keep status silent (no annoying bubbles)
       setStatus("");
 
+      if (map && v.length >= CLUSTER_THRESHOLD) {
+        const { fullCardPosts, clusterPosts } = splitForClusters(v);
+        const simpleVisible = clusterPosts.slice(0, SIMPLE_MARKER_LIMIT);
+        const clusterRemainder = clusterPosts.slice(SIMPLE_MARKER_LIMIT);
+        clusterModeRef.current = true;
+        ensureClusterLayers(map);
+        syncPriorityMarkers(fullCardPosts, simpleVisible);
+        updateClusterData(map, clusterRemainder);
+        setClusterVisibility(map, true);
+        return;
+      }
+
+      if (map && clusterModeRef.current) {
+        setClusterVisibility(map, false);
+        updateClusterData(map, []);
+        clusterModeRef.current = false;
+      }
+
       syncMarkers(v);
     },
-    [computeVisible, syncMarkers]
+    [computeVisible, syncMarkers, mapRef, ensureClusterLayers, updateClusterData, setClusterVisibility, splitForClusters, syncPriorityMarkers]
   );
 
   // On filter/search changes: recompute + sync (NO clear-all rebuild)
@@ -364,11 +649,9 @@ export function usePostsEngine({
         allPostsRef.current = Array.from(byId.values());
         lastFetchRef.current = { center: [...resolvedView.center], radiusKm, filterKey, timeFilter };
 
-        // Smooth update: sync markers + wall without clearing everything
+        // Smooth update: sync markers/clusters + wall without clearing everything
+        refreshVisibleAndMarkers(timeFilter);
         const visible = computeVisible(timeFilter);
-        setVisiblePosts((prev) => (sameIdList(prev, visible) ? prev : visible));
-        setStatus("");
-        syncMarkers(visible);
         if (
           !autoWidenRef.current &&
           timeFilter &&
@@ -399,6 +682,21 @@ export function usePostsEngine({
     };
   }, [viewParams, mapReady, mainFilter, subFilter, mapRef, timeFilter, expandedElRef, refreshVisibleAndMarkers, computeVisible, onAutoWidenTimeFilter, syncMarkers]);
 
+  useEffect(() => {
+    const map = mapRef.current;
+    if (!map) return;
+    const handleStyle = () => {
+      if (!clusterModeRef.current) return;
+      ensureClusterLayers(map);
+      setClusterVisibility(map, true);
+      const { clusterPosts } = splitForClusters(computeVisible(timeFilter));
+      const clusterRemainder = clusterPosts.slice(SIMPLE_MARKER_LIMIT);
+      updateClusterData(map, clusterRemainder);
+    };
+    map.on("styledata", handleStyle);
+    return () => map.off("styledata", handleStyle);
+  }, [mapRef, ensureClusterLayers, setClusterVisibility, updateClusterData, computeVisible, timeFilter, splitForClusters]);
+
   const handleIncomingPost = useCallback(
     (p) => {
       const key = getPostKey(p);
@@ -417,6 +715,11 @@ export function usePostsEngine({
       if (!matchesTimeFilter(p.created_at || p.CreatedAt || p.createdAt, timeFilter)) return;
       if (!matchesSearch(p, searchQuery)) return;
 
+      if (clusterModeRef.current) {
+        refreshVisibleAndMarkers(timeFilter);
+        return;
+      }
+
       // add marker if missing
       const id = getId(p);
       const have = new Set((markersRef.current || []).map((x) => x.id));
@@ -426,7 +729,7 @@ export function usePostsEngine({
 
       setVisiblePosts((current) => [...current, p]);
     },
-    [mainFilter, subFilter, timeFilter, searchQuery, mapRef, markersRef, expandedElRef, theme]
+    [mainFilter, subFilter, timeFilter, searchQuery, mapRef, markersRef, expandedElRef, theme, refreshVisibleAndMarkers]
   );
 
   return { status, visiblePosts, loadingPosts, loadError, handleIncomingPost };