diff --git a/public/packets.js b/public/packets.js
index d5eddcbf6..e4c3069db 100644
--- a/public/packets.js
+++ b/public/packets.js
@@ -770,7 +770,10 @@
   // lose their 120px cap; hops past the column edge go behind the +N pill).
   let showFullNames = localStorage.getItem('meshcore-full-names') === 'true';
   let _colFit = null; // fitColumnsToContent controller for #pktTable
-  var _pendingUrlRegion = null;
+  // Region/area filter listeners, removed in destroy() so a region change on
+  // another page doesn't reload packets and rewrite the URL to #/packets.
+  let _regionChangeHandler = null;
+  let _areaChangeHandler = null;
 
   var DEFAULT_TIME_WINDOW = 15;
 
@@ -1337,8 +1340,6 @@
       savedTimeWindowMin = _urlTimeWindow;
       localStorage.setItem('meshcore-time-window', String(_urlTimeWindow));
     }
-    var _urlRegion = _initUrlParams.get('region');
-    if (_urlRegion) _pendingUrlRegion = _urlRegion;
     var _urlHash = _initUrlParams.get('hash');
     if (_urlHash) filters.hash = _urlHash;
     var _urlNode = _initUrlParams.get('node');
@@ -1601,6 +1602,8 @@
     if (_docActionHandler) { document.removeEventListener('click', _docActionHandler); _docActionHandler = null; }
     if (_docMenuCloseHandler) { document.removeEventListener('click', _docMenuCloseHandler); _docMenuCloseHandler = null; }
     if (_docColMenuCloseHandler) { document.removeEventListener('click', _docColMenuCloseHandler); _docColMenuCloseHandler = null; }
+    if (_regionChangeHandler) { RegionFilter.offChange(_regionChangeHandler); _regionChangeHandler = null; }
+    if (_areaChangeHandler) { AreaFilter.offChange(_areaChangeHandler); _areaChangeHandler = null; }
     removeAllByopOverlays();
     packets = [];
     hashIndex = new Map();    selectedId = null;
@@ -1886,15 +1889,11 @@
       </table></div>
     `;
 
-    // Init shared RegionFilter component
+    // Init shared RegionFilter component (it applies a ?region= URL param itself)
     RegionFilter.init(document.getElementById('packetsRegionFilter'), { dropdown: true });
     AreaFilter.init(document.getElementById('packetsAreaFilter'));
-    if (_pendingUrlRegion) {
-      RegionFilter.setSelected(_pendingUrlRegion.split(',').filter(Boolean));
-      _pendingUrlRegion = null;
-    }
-    RegionFilter.onChange(function() { updatePacketsUrl(); loadPackets(); });
-    AreaFilter.onChange(function() { updatePacketsUrl(); loadPackets(); });
+    _regionChangeHandler = RegionFilter.onChange(function() { updatePacketsUrl(); loadPackets(); });
+    _areaChangeHandler = AreaFilter.onChange(function() { updatePacketsUrl(); loadPackets(); });
 
     // --- Packet Filter Language ---
     (function() {
diff --git a/public/region-filter.js b/public/region-filter.js
index 72a250a1b..135a680df 100644
--- a/public/region-filter.js
+++ b/public/region-filter.js
@@ -27,6 +27,9 @@
   }
 
   _selected = loadFromStorage();
+  // A ?region= link applies before any page reads the selection, so even a
+  // page that fetches before calling init() uses it on a fresh load.
+  applyUrlRegion();
 
   /** Fetch the configured quick picks. A failure only means no quick picks. */
   async function fetchQuickPicks() {
@@ -295,13 +298,49 @@
     _listeners = _listeners.filter(function (f) { return f !== fn; });
   }
 
+  /** Region codes from a ?region= hash param ("#/live?region=SJC,SFO"), or
+   *  null when the URL doesn't set one. */
+  function regionsFromUrl() {
+    if (typeof location === 'undefined' || !location.hash) return null;
+    var raw = new URLSearchParams(location.hash.split('?')[1] || '').get('region');
+    if (!raw) return null;
+    var codes = raw.split(',').map(function (c) { return c.trim(); }).filter(Boolean);
+    return codes.length > 0 ? codes : null;
+  }
+
+  /** Apply a ?region= URL param as the selection, saved like a click in the
+   *  control. Returns true when that changed the selection. */
+  function applyUrlRegion() {
+    var codes = regionsFromUrl();
+    if (!codes) return false;
+    // Once regions have loaded, fetchRegions() no longer cleans the selection,
+    // so drop unknown codes here; with none left, that's all regions, the same
+    // as the cleanup does on a fresh load.
+    if (_loaded) codes = codes.filter(function (c) { return Object.prototype.hasOwnProperty.call(_regions, c); });
+    var next = codes.length > 0 ? new Set(codes) : null;
+    var changed = !sameSelection(_selected, next);
+    _selected = next;
+    saveToStorage();
+    return changed;
+  }
+
   /** Initialize filter in a container, fetch regions, render, return promise.
-   *  Options: { dropdown: true } to force dropdown mode regardless of region count */
+   *  Options: { dropdown: true } to force dropdown mode regardless of region count
+   *
+   *  A ?region= param in the page's URL overrides the saved selection, so any
+   *  page with a region filter can be deep-linked to a region. On a fresh load
+   *  it was already applied when this script ran. On in-app navigation it's
+   *  applied here, before the await, so a page that loads after init() uses
+   *  it; if it changed the selection, listeners are told once regions load,
+   *  which reloads a page that fetched before calling init(). Unknown codes
+   *  are dropped either way. */
   async function initFilter(container, opts) {
     _container = container;
     if (opts && opts.dropdown) container._forceDropdown = true;
+    var urlChanged = applyUrlRegion();
     await fetchRegions();
     render(container);
+    if (urlChanged) _listeners.forEach(function (fn) { fn(getSelected()); });
   }
 
   /** True when two selections (Set or null = all) hold the same codes. */
diff --git a/test-all.sh b/test-all.sh
index 758731029..00a865185 100755
--- a/test-all.sh
+++ b/test-all.sh
@@ -203,6 +203,7 @@ node tests/unit/test-preflight-xss-gate.js
 node tests/unit/test-pull-to-reconnect-1091.js
 node tests/unit/test-pull-to-reconnect.js
 node tests/unit/test-region-filter-setselected.js
+node tests/unit/test-region-filter-url-param.js
 node tests/unit/test-repeater-metric-scatter.js
 node tests/unit/test-rx-coverage-config-race.js
 node tests/unit/test-rx-coverage-mine.js
diff --git a/tests/unit/test-issue-2012-clear-filters-selection.js b/tests/unit/test-issue-2012-clear-filters-selection.js
index f4b21e6b2..48846637f 100644
--- a/tests/unit/test-issue-2012-clear-filters-selection.js
+++ b/tests/unit/test-issue-2012-clear-filters-selection.js
@@ -273,7 +273,7 @@ test('#2091: list query builder never inherits detail observation', () => {
 test('#2091: init restores obs from the hash after router strips the query', () => {
   const readInitialObservation = new Function('location', 'routeParam',
     'let directObsId = "stale", directPacketId = null, directPacketHash = null; ' +
-    'let savedTimeWindowMin = 15, _pendingUrlRegion = null; const filters = {}, window = {}; ' +
+    'let savedTimeWindowMin = 15; const filters = {}, window = {}; ' +
     'let showFullNames = false; const localStorage = { getItem: () => null, setItem() {} }; ' +
     hashParamsSrc + '\n' + initParamsSrc + '\nreturn directObsId;');
   for (const route of ['aabbccddeeff0011', 'id/42']) {
diff --git a/tests/unit/test-region-filter-url-param.js b/tests/unit/test-region-filter-url-param.js
new file mode 100644
index 000000000..536c6ef66
--- /dev/null
+++ b/tests/unit/test-region-filter-url-param.js
@@ -0,0 +1,185 @@
+/**
+ * RegionFilter reads ?region= from the page's hash URL.
+ *
+ * Only the packets page honored ?region= (with its own one-off code); every
+ * other page with a region filter (live, nodes, observers, channels,
+ * analytics, scope audit) ignored it, so a link like #/live?region=SJC opened
+ * with whatever region the visitor last picked. RegionFilter now applies the
+ * param itself: it overrides the saved selection and is saved like a click in
+ * the control. On a fresh load it's in place when the script runs, before any
+ * page reads it (live fetches nodes before calling init). On in-app
+ * navigation init() applies it and, if that changed the selection, notifies
+ * listeners so a page that already fetched reloads. Unknown codes are dropped
+ * once regions load.
+ */
+'use strict';
+const REPO_ROOT = require('node:path').resolve(__dirname, '..', '..');
+const vm = require('node:vm');
+const fs = require('node:fs');
+const assert = require('node:assert');
+
+let passed = 0, failed = 0;
+async function test(name, fn) {
+  try { await fn(); passed++; console.log(`  ✓ ${name}`); }
+  catch (e) { failed++; console.error(`  ✗ ${name}: ${e.message}`); }
+}
+
+const REGIONS = { SJC: 'San Jose', SFO: 'San Francisco', OAK: 'Oakland' };
+
+function buildCtx(hash, initialStorage) {
+  const storage = Object.assign(Object.create(null), initialStorage || {});
+  const ctx = {
+    window: {},
+    location: { hash: hash || '' },
+    document: { addEventListener() {}, removeEventListener() {} },
+    localStorage: {
+      getItem: (k) => (k in storage ? storage[k] : null),
+      setItem: (k, v) => { storage[k] = String(v); },
+      removeItem: (k) => { delete storage[k]; },
+    },
+    fetch: async (url) => ({ json: async () => (url === '/api/config/regions' ? REGIONS : {}) }),
+    URLSearchParams, console, setTimeout, clearTimeout,
+  };
+  ctx.window = ctx;
+  vm.createContext(ctx);
+  vm.runInContext(fs.readFileSync(REPO_ROOT + '/public/region-filter.js', 'utf8'), ctx);
+  return { rf: ctx.window.RegionFilter, storage, location: ctx.location };
+}
+
+function container() {
+  return { innerHTML: '', style: {}, querySelector: () => null, contains: () => false };
+}
+
+(async () => {
+  console.log('RegionFilter applies a ?region= URL param');
+
+  await test('URL region overrides the saved selection', async () => {
+    const { rf } = buildCtx('#/live?region=SJC', { 'meshcore-region-filter': '["SFO"]' });
+    await rf.init(container());
+    assert.deepStrictEqual(Array.from(rf.getSelected()), ['SJC']);
+  });
+
+  await test('comma-separated codes are all selected, whitespace trimmed', async () => {
+    const { rf } = buildCtx('#/nodes?region=SJC,%20SFO');
+    await rf.init(container());
+    assert.deepStrictEqual(Array.from(rf.getSelected()), ['SJC', 'SFO']);
+  });
+
+  await test('fresh load: selection is in place before init is even called', () => {
+    const { rf } = buildCtx('#/live?region=SFO', { 'meshcore-region-filter': '["SJC"]' });
+    assert.deepStrictEqual(Array.from(rf.getSelected()), ['SFO']);
+    assert.strictEqual(rf.regionQueryString(), '&region=SFO');
+  });
+
+  await test('fresh load: init does not notify (nothing changed since the script ran)', async () => {
+    const { rf } = buildCtx('#/live?region=SFO');
+    const calls = [];
+    const p = rf.init(container());
+    rf.onChange((sel) => calls.push(sel && Array.from(sel)));
+    await p;
+    assert.deepStrictEqual(calls, []);
+  });
+
+  await test('in-app navigation: a changed region notifies listeners once regions load', async () => {
+    const { rf, location } = buildCtx('#/packets', { 'meshcore-region-filter': '["SJC"]' });
+    location.hash = '#/live?region=OAK';
+    const calls = [];
+    // live registers its listener right after calling init(), without awaiting
+    const p = rf.init(container());
+    rf.onChange((sel) => calls.push(sel && Array.from(sel)));
+    assert.deepStrictEqual(Array.from(rf.getSelected()), ['OAK']);
+    await p;
+    assert.deepStrictEqual(calls, [['OAK']]);
+  });
+
+  await test('in-app navigation: the same region as already selected does not notify', async () => {
+    const { rf, location } = buildCtx('#/packets', { 'meshcore-region-filter': '["OAK"]' });
+    location.hash = '#/live?region=OAK';
+    const calls = [];
+    const p = rf.init(container());
+    rf.onChange((sel) => calls.push(sel && Array.from(sel)));
+    await p;
+    assert.deepStrictEqual(calls, []);
+  });
+
+  await test('selection is in place before init resolves (callers do not await it)', () => {
+    const { rf } = buildCtx('#/nodes?region=OAK');
+    rf.init(container());
+    assert.deepStrictEqual(Array.from(rf.getSelected()), ['OAK']);
+    assert.strictEqual(rf.regionQueryString(), '&region=OAK');
+  });
+
+  await test('URL selection is saved like a click in the control', async () => {
+    const { rf, storage } = buildCtx('#/live?region=SFO');
+    await rf.init(container());
+    assert.strictEqual(storage['meshcore-region-filter'], '["SFO"]');
+  });
+
+  await test('unknown codes are dropped once regions load', async () => {
+    const { rf } = buildCtx('#/live?region=SJC,XXX');
+    await rf.init(container());
+    assert.deepStrictEqual(Array.from(rf.getSelected()), ['SJC']);
+  });
+
+  // fetchRegions() only cleans the selection on its first call, so on in-app
+  // navigation applyUrlRegion() must drop unknown codes itself.
+  await test('in-app navigation: unknown codes are dropped', async () => {
+    const { rf, location, storage } = buildCtx('#/packets');
+    await rf.init(container());
+    location.hash = '#/nodes?region=SJC,XXX';
+    await rf.init(container());
+    assert.deepStrictEqual(Array.from(rf.getSelected()), ['SJC']);
+    assert.strictEqual(rf.regionQueryString(), '&region=SJC');
+    assert.strictEqual(storage['meshcore-region-filter'], '["SJC"]');
+  });
+
+  await test('in-app navigation: only unknown codes means all regions', async () => {
+    const { rf, location, storage } = buildCtx('#/packets', { 'meshcore-region-filter': '["SFO"]' });
+    await rf.init(container());
+    location.hash = '#/nodes?region=XXX';
+    await rf.init(container());
+    assert.strictEqual(rf.getSelected(), null);
+    assert.strictEqual(rf.regionQueryString(), '');
+    assert.ok(!('meshcore-region-filter' in storage));
+  });
+
+  await test('no region param keeps the saved selection', async () => {
+    const { rf } = buildCtx('#/live?node=abc', { 'meshcore-region-filter': '["SFO"]' });
+    await rf.init(container());
+    assert.deepStrictEqual(Array.from(rf.getSelected()), ['SFO']);
+  });
+
+  await test('an empty region param keeps the saved selection', async () => {
+    const { rf } = buildCtx('#/live?region=', { 'meshcore-region-filter': '["SFO"]' });
+    await rf.init(container());
+    assert.deepStrictEqual(Array.from(rf.getSelected()), ['SFO']);
+  });
+
+  await test('no hash at all keeps "all regions"', async () => {
+    const { rf } = buildCtx('');
+    await rf.init(container());
+    assert.strictEqual(rf.getSelected(), null);
+  });
+
+  // packets.js registered its region/area listeners without keeping a handle,
+  // so they outlived the page: after visiting packets, a region change on any
+  // other page reloaded packets and replaceState'd the URL to #/packets. The
+  // in-app notify above makes that fire on every region link, so packets must
+  // remove both listeners in destroy().
+  console.log('packets.js removes its region/area listeners on destroy');
+  const pktSrc = fs.readFileSync(REPO_ROOT + '/public/packets.js', 'utf8');
+  const destroySrc = pktSrc.slice(pktSrc.indexOf('  function destroy() {'), pktSrc.indexOf('\n  }\n', pktSrc.indexOf('  function destroy() {')));
+
+  await test('listeners are registered with a kept handle', () => {
+    assert.match(pktSrc, /_regionChangeHandler = RegionFilter\.onChange\(/);
+    assert.match(pktSrc, /_areaChangeHandler = AreaFilter\.onChange\(/);
+  });
+
+  await test('destroy() removes both listeners', () => {
+    assert.match(destroySrc, /RegionFilter\.offChange\(_regionChangeHandler\)/);
+    assert.match(destroySrc, /AreaFilter\.offChange\(_areaChangeHandler\)/);
+  });
+
+  console.log(`\n${passed} passed, ${failed} failed`);
+  if (failed) process.exit(1);
+})();