@@ -72,6 +72,9 @@ export class Recognizer {
   private absoluteRedirectCount = 0;
   allowRedirects = true;
 
+  /** Shared by every snapshot: query params belong to the URL, not to any one route. */
+  private queryParams: Params;
+
   constructor(
     private injector: EnvironmentInjector,
     private configLoader: RouterConfigLoader,
@@ -83,6 +86,7 @@ export class Recognizer {
     private readonly abortSignal: AbortSignal,
   ) {
     this.applyRedirects = new ApplyRedirects(this.urlSerializer, this.urlTree);
+    this.queryParams = Object.freeze({...this.urlTree.queryParams});
   }
 
   private noMatchError(e: NoMatch): RuntimeError<RuntimeErrorCode.NO_MATCH> {
@@ -123,7 +127,7 @@ export class Recognizer {
     const rootSnapshot = new ActivatedRouteSnapshot(
       [],
       Object.freeze({}),
-      Object.freeze({...this.urlTree.queryParams}),
+      this.queryParams,
       this.urlTree.fragment,
       Object.freeze({}),
       PRIMARY_OUTLET,
@@ -144,6 +148,7 @@ export class Recognizer {
     } catch (e: any) {
       if (e instanceof AbsoluteRedirect) {
         this.urlTree = e.urlTree;
+        this.queryParams = Object.freeze({...this.urlTree.queryParams});
         return this.match(e.urlTree.root);
       }
       if (e instanceof NoMatch) {
@@ -384,7 +389,7 @@ export class Recognizer {
     const snapshot = new ActivatedRouteSnapshot(
       segments,
       parameters,
-      Object.freeze({...this.urlTree.queryParams}),
+      this.queryParams,
       this.urlTree.fragment,
       getData(route),
       getOutlet(route),
@@ -394,8 +399,8 @@ export class Recognizer {
       injector,
     );
     const inherited = getInherited(snapshot, parentRoute, this.paramsInheritanceStrategy);
-    snapshot.params = Object.freeze(inherited.params);
-    snapshot.data = Object.freeze(inherited.data);
+    snapshot.params = inherited.params;
+    snapshot.data = inherited.data;
     return snapshot;
   }
 
 
@@ -325,8 +325,12 @@ export function getInherited(
       (!parent.component && !parent.routeConfig?.loadComponent))
   ) {
     inherited = {
-      params: {...parent.params, ...route.params},
-      data: {...parent.data, ...route.data},
+      // Reuse the parent's frozen params when the route adds none of its own.
+      params:
+        Object.keys(route.params).length === 0
+          ? parent.params
+          : Object.freeze({...parent.params, ...route.params}),
+      data: Object.freeze({...parent.data, ...route.data}),
       resolve: {
         // Snapshots are created with data inherited from parent and guards (i.e. canActivate) can
         // change data because it's not frozen...
@@ -345,8 +349,8 @@ export function getInherited(
     };
   } else {
     inherited = {
-      params: {...route.params},
-      data: {...route.data},
+      params: Object.freeze({...route.params}),
+      data: Object.freeze({...route.data}),
       resolve: {...route.data, ...(route._resolvedData ?? {})},
     };
   }
 
@@ -1144,8 +1144,58 @@ describe('recognize', () => {
       await expectAsync(recognizer('foo/bar')).toBeRejected();
     });
   });
+
+  describe('snapshot creation', () => {
+    it('shares one queryParams object across every snapshot', async () => {
+      const s = await recognize(
+        [{path: 'a', children: [{path: '', children: [{path: '', component: ComponentA}]}]}],
+        'a/(x:/()//y:/()//z:/())?p=1&q=2',
+      );
+      const snapshots = collectSnapshots(s.root);
+      expect(snapshots.length).toBeGreaterThan(1);
+      for (const snapshot of snapshots) {
+        expect(snapshot.queryParams).toBe(s.root.queryParams);
+      }
+      expect(s.root.queryParams).toEqual({p: '1', q: '2'});
+      expect(Object.isFrozen(s.root.queryParams)).toBeTrue();
+    });
+
+    it('shares the parent params with a route that adds none of its own', async () => {
+      const s = await recognize(
+        [
+          {
+            path: 'a',
+            children: [
+              {path: '', component: ComponentA},
+              {path: '', outlet: 'modal', component: ComponentB},
+            ],
+          },
+        ],
+        'a;x=1/(modal:/())',
+      );
+      const a = s.root.firstChild!;
+      expect(a.params).toEqual({x: '1'});
+      // An empty path route matches once for every outlet the URL names.
+      expect(a.children.length).toBe(2);
+      for (const child of a.children) {
+        expect(child.params).toBe(a.params);
+        expect(Object.isFrozen(child.params)).toBeTrue();
+      }
+    });
+  });
 });
 
+function collectSnapshots(
+  snapshot: ActivatedRouteSnapshot,
+  into: ActivatedRouteSnapshot[] = [],
+): ActivatedRouteSnapshot[] {
+  into.push(snapshot);
+  for (const child of snapshot.children) {
+    collectSnapshots(child, into);
+  }
+  return into;
+}
+
 async function recognize(
   config: Routes,
   url: string,