diff --git a/.gitignore b/.gitignore
index 31e3542..9944c52 100644
--- a/.gitignore
+++ b/.gitignore
@@ -50,4 +50,7 @@ docs/comparison-*.md
 
 # Local dev tools (mock servers, screenshot automation)
 tools/dev/
+
+# PMTiles map data (large binaries, downloaded per-region)
+frontend/public/tiles/*.pmtiles
 fleet-dashboard.png
diff --git a/docker-compose.override.yml b/docker-compose.override.yml
index 9bcf228..6e3cb6e 100644
--- a/docker-compose.override.yml
+++ b/docker-compose.override.yml
@@ -135,6 +135,8 @@ services:
     container_name: tod_frontend
     ports:
       - "3000:80"
+    volumes:
+      - ./frontend/public/tiles:/usr/share/nginx/html/tiles:ro
     depends_on:
       - api
     deploy:
diff --git a/frontend/package-lock.json b/frontend/package-lock.json
index 5e1a8ff..1a31174 100644
--- a/frontend/package-lock.json
+++ b/frontend/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "frontend",
-  "version": "9.0.1",
+  "version": "9.7.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "frontend",
-      "version": "9.0.1",
+      "version": "9.7.0",
       "dependencies": {
         "@dagrejs/dagre": "^2.0.4",
         "@fontsource-variable/manrope": "^5.2.8",
@@ -43,6 +43,7 @@
         "framer-motion": "^12.34.3",
         "leaflet": "^1.9.4",
         "lucide-react": "^0.575.0",
+        "protomaps-leaflet": "^5.1.0",
         "react": "^19.2.0",
         "react-dom": "^19.2.0",
         "react-leaflet": "^5.0.0",
@@ -1416,6 +1417,23 @@
         "@jridgewell/sourcemap-codec": "^1.4.14"
       }
     },
+    "node_modules/@mapbox/point-geometry": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/@mapbox/point-geometry/-/point-geometry-1.1.0.tgz",
+      "integrity": "sha512-YGcBz1cg4ATXDCM/71L9xveh4dynfGmcLDqufR+nQQy3fKwsAZsWd/x4621/6uJaeB9mwOHE6hPeDgXz9uViUQ==",
+      "license": "ISC"
+    },
+    "node_modules/@mapbox/vector-tile": {
+      "version": "2.0.4",
+      "resolved": "https://registry.npmjs.org/@mapbox/vector-tile/-/vector-tile-2.0.4.tgz",
+      "integrity": "sha512-AkOLcbgGTdXScosBWwmmD7cDlvOjkg/DetGva26pIRiZPdeJYjYKarIlb4uxVzi6bwHO6EWH82eZ5Nuv4T5DUg==",
+      "license": "BSD-3-Clause",
+      "dependencies": {
+        "@mapbox/point-geometry": "~1.1.0",
+        "@types/geojson": "^7946.0.16",
+        "pbf": "^4.0.1"
+      }
+    },
     "node_modules/@nodelib/fs.scandir": {
       "version": "2.1.5",
       "resolved": "https://registry.npmjs.org/@nodelib/fs.scandir/-/fs.scandir-2.1.5.tgz",
@@ -1467,6 +1485,15 @@
         "node": ">=18"
       }
     },
+    "node_modules/@protomaps/basemaps": {
+      "version": "5.7.2",
+      "resolved": "https://registry.npmjs.org/@protomaps/basemaps/-/basemaps-5.7.2.tgz",
+      "integrity": "sha512-K1Yk6bWdULulYg+R2QRVXx4NzJZan5YQhpejEG0c1/sXruJrfPIPZuakpf3jwAgVmjIRVQwAv+yRafDeN0aaUQ==",
+      "license": "BSD-3-Clause",
+      "bin": {
+        "generate_style": "src/cli.ts"
+      }
+    },
     "node_modules/@radix-ui/number": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/@radix-ui/number/-/number-1.1.1.tgz",
@@ -4331,6 +4358,12 @@
         "assertion-error": "^2.0.1"
       }
     },
+    "node_modules/@types/css-font-loading-module": {
+      "version": "0.0.7",
+      "resolved": "https://registry.npmjs.org/@types/css-font-loading-module/-/css-font-loading-module-0.0.7.tgz",
+      "integrity": "sha512-nl09VhutdjINdWyXxHWN/w9zlNCfr60JUqJbd24YXUuCwgeL0TpFSdElCwb6cxfB6ybE19Gjj4g0jsgkXxKv1Q==",
+      "license": "MIT"
+    },
     "node_modules/@types/d3": {
       "version": "7.4.3",
       "resolved": "https://registry.npmjs.org/@types/d3/-/d3-7.4.3.tgz",
@@ -4631,7 +4664,6 @@
       "version": "1.9.21",
       "resolved": "https://registry.npmjs.org/@types/leaflet/-/leaflet-1.9.21.tgz",
       "integrity": "sha512-TbAd9DaPGSnzp6QvtYngntMZgcRk+igFELwR2N99XZn7RXUdKgsXMR+28bUO0rPsWp8MIu/f47luLIQuSLYv/w==",
-      "dev": true,
       "license": "MIT",
       "dependencies": {
         "@types/geojson": "*"
@@ -4647,6 +4679,12 @@
         "undici-types": "~7.16.0"
       }
     },
+    "node_modules/@types/rbush": {
+      "version": "3.0.4",
+      "resolved": "https://registry.npmjs.org/@types/rbush/-/rbush-3.0.4.tgz",
+      "integrity": "sha512-knSt9cCW8jj1ZSFcFeBZaX++OucmfPxxHiRwTahZfJlnQsek7O0bazTJHWD2RVj9LEoejUYF2de3/stf+QXcXw==",
+      "license": "MIT"
+    },
     "node_modules/@types/react": {
       "version": "19.2.14",
       "resolved": "https://registry.npmjs.org/@types/react/-/react-19.2.14.tgz",
@@ -5677,6 +5715,12 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/color2k": {
+      "version": "2.0.3",
+      "resolved": "https://registry.npmjs.org/color2k/-/color2k-2.0.3.tgz",
+      "integrity": "sha512-zW190nQTIoXcGCaU08DvVNFTmQhUpnJfVuAKfWqUQkflXKpaDdpaYoM0iluLS9lgJNHyBF58KKA2FBEwkD7wog==",
+      "license": "MIT"
+    },
     "node_modules/combined-stream": {
       "version": "1.0.8",
       "resolved": "https://registry.npmjs.org/combined-stream/-/combined-stream-1.0.8.tgz",
@@ -6572,6 +6616,12 @@
         }
       }
     },
+    "node_modules/fflate": {
+      "version": "0.8.2",
+      "resolved": "https://registry.npmjs.org/fflate/-/fflate-0.8.2.tgz",
+      "integrity": "sha512-cPJU47OaAoCbg0pBvzsgpTPhmhqI5eJjh/JIu8tPj5q+T7iLvW/JAYUqmE7KOB4R1ZyEhzBaIQpQpardBF5z8A==",
+      "license": "MIT"
+    },
     "node_modules/file-entry-cache": {
       "version": "8.0.0",
       "resolved": "https://registry.npmjs.org/file-entry-cache/-/file-entry-cache-8.0.0.tgz",
@@ -7652,6 +7702,18 @@
       "integrity": "sha512-WUjGcAqP1gQacoQe+OBJsFA7Ld4DyXuUIjZ5cc75cLHvJ7dtNsTugphxIADwspS+AraAUePCKrSVtPLFj/F88w==",
       "license": "MIT"
     },
+    "node_modules/pbf": {
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/pbf/-/pbf-4.0.1.tgz",
+      "integrity": "sha512-SuLdBvS42z33m8ejRbInMapQe8n0D3vN/Xd5fmWM3tufNgRQFBpaW2YVJxQZV4iPNqb0vEFvssMEo5w9c6BTIA==",
+      "license": "BSD-3-Clause",
+      "dependencies": {
+        "resolve-protobuf-schema": "^2.1.0"
+      },
+      "bin": {
+        "pbf": "bin/pbf"
+      }
+    },
     "node_modules/picocolors": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/picocolors/-/picocolors-1.1.1.tgz",
@@ -7735,6 +7797,16 @@
         "node": "^8.16.0 || ^10.6.0 || >=11.0.0"
       }
     },
+    "node_modules/pmtiles": {
+      "version": "3.2.1",
+      "resolved": "https://registry.npmjs.org/pmtiles/-/pmtiles-3.2.1.tgz",
+      "integrity": "sha512-3R4fBwwoli5mw7a6t1IGwOtfmcSAODq6Okz0zkXhS1zi9sz1ssjjIfslwPvcWw5TNhdjNBUg9fgfPLeqZlH6ng==",
+      "license": "BSD-3-Clause",
+      "dependencies": {
+        "@types/leaflet": "^1.9.8",
+        "fflate": "^0.8.0"
+      }
+    },
     "node_modules/postcss": {
       "version": "8.5.6",
       "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.6.tgz",
@@ -7891,6 +7963,12 @@
       "integrity": "sha512-1NNCs6uurfkVbeXG4S8JFT9t19m45ICnif8zWLd5oPSZ50QnwMfK+H3jv408d4jw/7Bttv5axS5IiHoLaVNHeQ==",
       "license": "MIT"
     },
+    "node_modules/potpack": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/potpack/-/potpack-1.0.2.tgz",
+      "integrity": "sha512-choctRBIV9EMT9WGAZHn3V7t0Z2pMQyl0EZE6pFc/6ml3ssw7Dlf/oAOvFwjm1HVsqfQN8GfeFyJ+d8tRzqueQ==",
+      "license": "ISC"
+    },
     "node_modules/prelude-ls": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/prelude-ls/-/prelude-ls-1.2.1.tgz",
@@ -7954,6 +8032,30 @@
       "license": "MIT",
       "peer": true
     },
+    "node_modules/protocol-buffers-schema": {
+      "version": "3.6.0",
+      "resolved": "https://registry.npmjs.org/protocol-buffers-schema/-/protocol-buffers-schema-3.6.0.tgz",
+      "integrity": "sha512-TdDRD+/QNdrCGCE7v8340QyuXd4kIWIgapsE2+n/SaGiSSbomYl4TjHlvIoCWRpE7wFt02EpB35VVA2ImcBVqw==",
+      "license": "MIT"
+    },
+    "node_modules/protomaps-leaflet": {
+      "version": "5.1.0",
+      "resolved": "https://registry.npmjs.org/protomaps-leaflet/-/protomaps-leaflet-5.1.0.tgz",
+      "integrity": "sha512-N0YY1Gbw5nZ9n8VUOvwHKm/w3zhTTuaZEeMZl8doHemeM4ujGPp2otI6t4Sgqrz8iM4svx2rpG1Q17rHkOWSaA==",
+      "license": "BSD-3-Clause",
+      "dependencies": {
+        "@mapbox/point-geometry": "^1.1.0",
+        "@mapbox/vector-tile": "^2.0.2",
+        "@protomaps/basemaps": "^5.0.0",
+        "@types/css-font-loading-module": "^0.0.7",
+        "@types/rbush": "^3.0.0",
+        "color2k": "^2.0.3",
+        "pbf": "^4.0.1",
+        "pmtiles": "^3.1.0",
+        "potpack": "^1.0.2",
+        "rbush": "^3.0.1"
+      }
+    },
     "node_modules/proxy-from-env": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/proxy-from-env/-/proxy-from-env-1.1.0.tgz",
@@ -7990,6 +8092,21 @@
       ],
       "license": "MIT"
     },
+    "node_modules/quickselect": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/quickselect/-/quickselect-2.0.0.tgz",
+      "integrity": "sha512-RKJ22hX8mHe3Y6wH/N3wCM6BWtjaxIyyUIkpHOvfFnxdI4yD4tBXEBKSbriGujF6jnSVkJrffuo6vxACiSSxIw==",
+      "license": "ISC"
+    },
+    "node_modules/rbush": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/rbush/-/rbush-3.0.1.tgz",
+      "integrity": "sha512-XRaVO0YecOpEuIvbhbpTrZgoiI6xBlz6hnlr6EHhd+0x9ase6EmeN+hdwwUaJvLcsFFQ8iWVF1GAK1yB0BWi0w==",
+      "license": "MIT",
+      "dependencies": {
+        "quickselect": "^2.0.0"
+      }
+    },
     "node_modules/react": {
       "version": "19.2.4",
       "resolved": "https://registry.npmjs.org/react/-/react-19.2.4.tgz",
@@ -8354,6 +8471,15 @@
         "url": "https://github.com/privatenumber/resolve-pkg-maps?sponsor=1"
       }
     },
+    "node_modules/resolve-protobuf-schema": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/resolve-protobuf-schema/-/resolve-protobuf-schema-2.1.0.tgz",
+      "integrity": "sha512-kI5ffTiZWmJaS/huM8wZfEMer1eRd7oJQhDuxeCLe3t7N7mX3z94CN0xPxBQxFYQTSNz9T0i+v6inKqSdK8xrQ==",
+      "license": "MIT",
+      "dependencies": {
+        "protocol-buffers-schema": "^3.3.1"
+      }
+    },
     "node_modules/reusify": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/reusify/-/reusify-1.1.0.tgz",
diff --git a/frontend/package.json b/frontend/package.json
index a44d25a..827f349 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -50,6 +50,7 @@
     "framer-motion": "^12.34.3",
     "leaflet": "^1.9.4",
     "lucide-react": "^0.575.0",
+    "protomaps-leaflet": "^5.1.0",
     "react": "^19.2.0",
     "react-dom": "^19.2.0",
     "react-leaflet": "^5.0.0",
diff --git a/frontend/src/components/map/FleetMap.tsx b/frontend/src/components/map/FleetMap.tsx
index 7287ee6..b6b8202 100644
--- a/frontend/src/components/map/FleetMap.tsx
+++ b/frontend/src/components/map/FleetMap.tsx
@@ -1,7 +1,8 @@
 import { useEffect, useMemo } from 'react'
-import { MapContainer, TileLayer, useMap } from 'react-leaflet'
+import { MapContainer, useMap } from 'react-leaflet'
 import MarkerClusterGroup from 'react-leaflet-cluster'
 import L from 'leaflet'
+import * as protomapsL from 'protomaps-leaflet'
 import type { FleetDevice } from '@/lib/api'
 import { DeviceMarker } from './DeviceMarker'
 
@@ -16,6 +17,31 @@ interface FleetMapProps {
 const DEFAULT_CENTER: [number, number] = [20, 0]
 const DEFAULT_ZOOM = 2
 
+/**
+ * Self-hosted PMTiles basemap layer via protomaps-leaflet.
+ * Loads regional PMTiles files from /tiles/ (no third-party requests).
+ * Multiple region files are layered — tiles outside downloaded regions show blank.
+ */
+const PMTILES_REGIONS = ['/tiles/wisconsin.pmtiles', '/tiles/florida.pmtiles']
+
+function ProtomapsLayer() {
+  const map = useMap()
+
+  useEffect(() => {
+    const layers: L.Layer[] = []
+    for (const url of PMTILES_REGIONS) {
+      const layer = protomapsL.leafletLayer({ url, flavor: 'dark' })
+      layer.addTo(map)
+      layers.push(layer)
+    }
+    return () => {
+      for (const layer of layers) map.removeLayer(layer)
+    }
+  }, [map])
+
+  return null
+}
+
 /**
  * Inner component that auto-fits the map to device bounds
  * whenever the device list changes.
@@ -111,10 +137,7 @@ export function FleetMap({ devices, tenantId }: FleetMapProps) {
       scrollWheelZoom
       style={{ background: 'hsl(var(--background))' }}
     >
-      <TileLayer
-        attribution='&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'
-        url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"
-      />
+      <ProtomapsLayer />
       <AutoFitBounds devices={mappedDevices} />
       <MarkerClusterGroup
         chunkedLoading
diff --git a/frontend/src/routes/_authenticated.tsx b/frontend/src/routes/_authenticated.tsx
index b42bc94..6f20a43 100644
--- a/frontend/src/routes/_authenticated.tsx
+++ b/frontend/src/routes/_authenticated.tsx
@@ -2,7 +2,7 @@ import { useCallback } from 'react'
 import { createFileRoute, Outlet, Navigate, redirect, useNavigate, useRouterState } from '@tanstack/react-router'
 import { useQueryClient } from '@tanstack/react-query'
 import { AnimatePresence } from 'framer-motion'
-import { toast } from 'sonner'
+// toast import removed — alert toasts were noisy at fleet scale
 import { useAuth } from '@/lib/auth'
 import { useUIStore } from '@/lib/store'
 import { useEventStream, type SSEEvent } from '@/hooks/useEventStream'
@@ -72,27 +72,8 @@ function AuthenticatedLayout() {
 
         // ── Alert fired (RT-03) ───────────────────────────────────────────
         case 'alert_fired': {
-          const { severity, rule_name, device_name, metric, current_value, threshold } =
-            event.data as {
-              severity: string
-              rule_name: string
-              device_name?: string
-              metric?: string
-              current_value?: string | number
-              threshold?: string | number
-            }
-          const toastFn =
-            severity === 'critical'
-              ? toast.error
-              : severity === 'warning'
-                ? toast.warning
-                : toast.info
-          toastFn(`Alert: ${rule_name}`, {
-            description: device_name
-              ? `${device_name} — ${metric ?? 'unknown'}: ${current_value ?? '?'} (threshold: ${threshold ?? '?'})`
-              : `${metric ?? 'unknown'}: ${current_value ?? '?'}`,
-            duration: severity === 'critical' ? 10000 : 5000,
-          })
+          // Invalidate alert queries so dashboard/alert pages update in real-time.
+          // No toast — at fleet scale these fire constantly and become noise.
           void queryClient.invalidateQueries({ queryKey: ['active-alerts'] })
           void queryClient.invalidateQueries({ queryKey: ['alert-events'] })
           void queryClient.invalidateQueries({ queryKey: ['dashboard-alerts'] })
@@ -101,14 +82,6 @@ function AuthenticatedLayout() {
 
         // ── Alert resolved ────────────────────────────────────────────────
         case 'alert_resolved': {
-          const { metric } = event.data as {
-            device_id?: string
-            metric?: string
-          }
-          toast.info('Alert resolved', {
-            description: `${metric ?? 'Condition'} returned to normal`,
-            duration: 3000,
-          })
           void queryClient.invalidateQueries({ queryKey: ['active-alerts'] })
           void queryClient.invalidateQueries({ queryKey: ['alert-events'] })
           void queryClient.invalidateQueries({ queryKey: ['dashboard-alerts'] })
diff --git a/infrastructure/docker/nginx-spa.conf b/infrastructure/docker/nginx-spa.conf
index aa36acf..128063b 100644
--- a/infrastructure/docker/nginx-spa.conf
+++ b/infrastructure/docker/nginx-spa.conf
@@ -23,7 +23,7 @@ server {
 
     # CSP for React SPA with Tailwind CSS and Leaflet maps
     # worker-src required for SRP key derivation Web Worker (Safari won't fall back to script-src)
-    add_header Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data: https://*.tile.openstreetmap.org; font-src 'self'; connect-src 'self' ws: wss:; worker-src 'self'; frame-ancestors 'self'; base-uri 'self'; form-action 'self';" always;
+    add_header Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob:; font-src 'self'; connect-src 'self' ws: wss:; worker-src 'self' blob:; frame-ancestors 'self'; base-uri 'self'; form-action 'self';" always;
 
     # Proxy API requests to the backend service
     # The api container is reachable via Docker internal DNS as "api" on port 8000
@@ -91,6 +91,16 @@ server {
         add_header X-Content-Type-Options "nosniff" always;
     }
 
+    # Serve PMTiles with byte range support (protomaps-leaflet reads via HTTP Range)
+    location /tiles/ {
+        add_header Access-Control-Allow-Origin "*" always;
+        add_header X-Content-Type-Options "nosniff" always;
+        types {
+            application/octet-stream pmtiles;
+        }
+        try_files $uri =404;
+    }
+
     # Serve static assets with long cache headers
     # Note: add_header in a location block clears parent-block headers,
     # so we re-add the essential security header for static assets.