diff --git a/packages/@ember/-internals/glimmer/lib/syntax/outlet.ts b/packages/@ember/-internals/glimmer/lib/syntax/outlet.ts
index 669ba8e58b9..debf7a97eb9 100644
--- a/packages/@ember/-internals/glimmer/lib/syntax/outlet.ts
+++ b/packages/@ember/-internals/glimmer/lib/syntax/outlet.ts
@@ -1,5 +1,5 @@
 import type { InternalOwner } from '@ember/-internals/owner';
-import { assert, deprecate } from '@ember/debug';
+import { assert } from '@ember/debug';
 import { DEBUG } from '@glimmer/env';
 import type { CapturedArguments, DynamicScope } from '@glimmer/interfaces';
 import { CurriedType } from '@glimmer/vm';
@@ -17,7 +17,6 @@ import type { OutletDefinitionState } from '../component-managers/outlet';
 import { OutletComponentDefinition } from '../component-managers/outlet';
 import { internalHelper } from '../helpers/internal-helper';
 import type { OutletState } from '../utils/outlet';
-import { isTemplateFactory } from '../template';
 
 /**
   The `{{outlet}}` helper lets you specify where a child route will render in
@@ -121,40 +120,6 @@ function stateFor(
   let template = render.template;
   if (template === undefined) return null;
 
-  if (isTemplateFactory(template)) {
-    template = template(render.owner);
-
-    if (DEBUG) {
-      let message =
-        'The `template` property of `OutletState` should be a ' +
-        '`Template` rather than a `TemplateFactory`. This is known to be a ' +
-        "problem in older versions of `@ember/test-helpers`. If you haven't " +
-        'done so already, try upgrading to the latest version.\n\n';
-
-      if (template.result === 'ok' && typeof template.moduleName === 'string') {
-        message +=
-          'The offending template has a moduleName `' +
-          template.moduleName +
-          '`, which might be helpful for identifying ' +
-          'source of this issue.\n\n';
-      }
-
-      message +=
-        'Please note that `OutletState` is a private API in Ember.js ' +
-        "and not meant to be used outside of the framework's internal code.";
-
-      deprecate(message, false, {
-        id: 'outlet-state-template-factory',
-        until: '5.9.0',
-        for: 'ember-source',
-        since: {
-          available: '5.6.0',
-          enabled: '5.6.0',
-        },
-      });
-    }
-  }
-
   return {
     ref,
     name: render.name,
diff --git a/packages/@ember/-internals/glimmer/lib/utils/outlet.ts b/packages/@ember/-internals/glimmer/lib/utils/outlet.ts
index 7fe032ae51f..741c4a20fd7 100644
--- a/packages/@ember/-internals/glimmer/lib/utils/outlet.ts
+++ b/packages/@ember/-internals/glimmer/lib/utils/outlet.ts
@@ -1,22 +1,6 @@
 import type { InternalOwner } from '@ember/-internals/owner';
 import type { Template } from '@glimmer/interfaces';
 
-// Note: a lot of these does not make sense anymore. This design was from back
-// when we supported "named outlets", where a route can do:
-//
-// this.renderTemplate("some-template", {
-//   into: 'some-parent-route',
-//   outlet: 'some-name' /* {{outlet "some-name"}} */ | undefined /* {{outlet}} */,
-//   controller: 'some-controller' | SomeController,
-//   model: { ... },
-// });
-//
-// And interface reflects that. Now that this is not supported anymore, each
-// route implicitly renders into its immediate parent's `{{outlet}}` (no name).
-// Keeping around most of these to their appropriately hardcoded values for the
-// time being to minimize churn for external consumers, as we are about to rip
-// all of it out anyway.
-
 export interface RenderState {
   /**
    * This is usually inherited from the parent (all the way up to the app
@@ -25,18 +9,6 @@ export interface RenderState {
    */
   owner: InternalOwner;
 
-  /**
-   * @deprecated This used to specify "which parent route to render into",
-   * which is not a thing anymore.
-   */
-  into: undefined;
-
-  /**
-   * @deprecated This used to specify "which named outlet in the parent
-   * template to render into", which is not a thing anymore.
-   */
-  outlet: 'main';
-
   /**
    * The name of the route/template
    */
@@ -53,7 +25,7 @@ export interface RenderState {
   model: unknown;
 
   /**
-   * template (the layout of the outlet component)
+   * The template (the route template to use in the {{outlet}})
    */
   template: Template | undefined;
 }
@@ -75,22 +47,4 @@ export interface OutletState {
   outlets: {
     main: OutletState | undefined;
   };
-
-  /**
-   * @deprecated
-   *
-   * This tracks whether this outlet state actually made it onto the page
-   * somewhere. This was more of a problem when you can declare named outlets
-   * left and right, and anything can render into anywhere else. We want to
-   * warn users when you tried to render into somewhere that does not exist,
-   * but we don't know what named outlets exists until after we have rendered
-   * everything, so this was used to track these orphan renders.
-   *
-   * This can still happen, if, according to the router, a route is active and
-   * so its template should be rendered, but the parent template is missing the
-   * `{{outlet}}` keyword, or that it was hidden by an `{{#if}}` or something.
-   * I guess that is considered valid, because nothing checks for this anymore.
-   * seems valid for the parent to decide not to render a child template?
-   */
-  wasUsed?: undefined;
 }
diff --git a/packages/@ember/-internals/glimmer/lib/views/outlet.ts b/packages/@ember/-internals/glimmer/lib/views/outlet.ts
index ced2115585d..dc97e2b6276 100644
--- a/packages/@ember/-internals/glimmer/lib/views/outlet.ts
+++ b/packages/@ember/-internals/glimmer/lib/views/outlet.ts
@@ -67,8 +67,6 @@ export default class OutletView {
       outlets: { main: undefined },
       render: {
         owner: owner,
-        into: undefined,
-        outlet: 'main',
         name: TOP_LEVEL_NAME,
         controller: undefined,
         model: undefined,
diff --git a/packages/@ember/-internals/glimmer/tests/integration/outlet-test.js b/packages/@ember/-internals/glimmer/tests/integration/outlet-test.js
index 193ee68354c..fc17ee2730e 100644
--- a/packages/@ember/-internals/glimmer/tests/integration/outlet-test.js
+++ b/packages/@ember/-internals/glimmer/tests/integration/outlet-test.js
@@ -16,8 +16,6 @@ moduleFor(
       let outletState = {
         render: {
           owner: this.owner,
-          into: undefined,
-          outlet: 'main',
           name: 'application',
           controller: undefined,
           template: undefined,
@@ -37,8 +35,6 @@ moduleFor(
       let outletState = {
         render: {
           owner: this.owner,
-          into: undefined,
-          outlet: 'main',
           name: 'application',
           controller: undefined,
           template: undefined,
@@ -57,8 +53,6 @@ moduleFor(
       outletState = {
         render: {
           owner: this.owner,
-          into: undefined,
-          outlet: 'main',
           name: 'application',
           controller: {},
           template: this.owner.lookup('template:application')(this.owner),
@@ -76,8 +70,6 @@ moduleFor(
       outletState.outlets.main = {
         render: {
           owner: this.owner,
-          into: undefined,
-          outlet: 'main',
           name: 'index',
           controller: {},
           template: this.owner.lookup('template:index')(this.owner),
@@ -95,8 +87,6 @@ moduleFor(
       let outletState = {
         render: {
           owner: this.owner,
-          into: undefined,
-          outlet: 'main',
           name: 'application',
           controller: {},
           template: this.owner.lookup('template:application')(this.owner),
@@ -116,8 +106,6 @@ moduleFor(
       outletState.outlets.main = {
         render: {
           owner: this.owner,
-          into: undefined,
-          outlet: 'main',
           name: 'index',
           controller: {},
           template: this.owner.lookup('template:index')(this.owner),
@@ -146,8 +134,6 @@ moduleFor(
       let outletState = {
         render: {
           owner: this.owner,
-          into: undefined,
-          outlet: 'main',
           name: 'outer',
           controller: {},
           template: this.owner.lookup('template:outer')(this.owner),
@@ -156,8 +142,6 @@ moduleFor(
           main: {
             render: {
               owner: this.owner,
-              into: undefined,
-              outlet: 'main',
               name: 'inner',
               controller: {},
               template: this.owner.lookup('template:inner')(this.owner),
diff --git a/packages/@ember/routing/route.ts b/packages/@ember/routing/route.ts
index c407f629caf..cfab81cfe5a 100644
--- a/packages/@ember/routing/route.ts
+++ b/packages/@ember/routing/route.ts
@@ -1842,8 +1842,6 @@ function buildRenderState(route: Route): RenderState {
 
   let render: RenderState = {
     owner,
-    into: undefined,
-    outlet: 'main',
     name,
     controller,
     model,
diff --git a/packages/ember/tests/ember-test-helpers-test.js b/packages/ember/tests/ember-test-helpers-test.js
index d08e271cea6..5dee7cfe4c5 100644
--- a/packages/ember/tests/ember-test-helpers-test.js
+++ b/packages/ember/tests/ember-test-helpers-test.js
@@ -85,8 +85,6 @@ module('@ember/test-helpers emulation test', function () {
       let outletState = {
         render: {
           owner,
-          into: undefined,
-          outlet: 'main',
           name: 'application',
           controller: undefined,
           ViewClass: undefined,
@@ -97,8 +95,6 @@ module('@ember/test-helpers emulation test', function () {
           main: {
             render: {
               owner,
-              into: undefined,
-              outlet: 'main',
               name: 'index',
               controller: context,
               ViewClass: undefined,
@@ -138,124 +134,4 @@ module('@ember/test-helpers emulation test', function () {
       });
     });
   });
-
-  module('v1.6.0', function () {
-    let EMPTY_TEMPLATE = compile('');
-
-    function settled() {
-      return new Promise(function (resolve) {
-        let watcher = setInterval(() => {
-          if (_getCurrentRunLoop() || _hasScheduledTimers()) {
-            return;
-          }
-
-          // Stop polling
-          clearInterval(watcher);
-
-          // Synchronously resolve the promise
-          run(null, resolve);
-        }, 10);
-      });
-    }
-
-    async function setupContext(context) {
-      // condensed version of https://github.com/emberjs/ember-test-helpers/blob/v1.6.0/addon-test-support/%40ember/test-helpers/build-owner.ts#L38
-      // without support for "custom resolver"
-      await context.application.boot();
-
-      context.owner = await context.application.buildInstance().boot();
-    }
-
-    function setupRenderingContext(context) {
-      let { owner } = context;
-      let OutletView = owner.factoryFor('view:-outlet');
-      let environment = owner.lookup('-environment:main');
-      let outletTemplateFactory = owner.lookup('template:-outlet');
-      let toplevelView = OutletView.create({ environment, template: outletTemplateFactory });
-
-      owner.register('-top-level-view:main', {
-        create() {
-          return toplevelView;
-        },
-      });
-
-      // initially render a simple empty template
-      return render(EMPTY_TEMPLATE, context).then(() => {
-        let rootElement = document.querySelector(owner.rootElement);
-        run(toplevelView, 'appendTo', rootElement);
-
-        context.element = rootElement;
-
-        return settled();
-      });
-    }
-
-    let templateId = 0;
-    function render(template, context) {
-      let { owner } = context;
-      let toplevelView = owner.lookup('-top-level-view:main');
-      templateId += 1;
-      let templateFullName = `template:-undertest-${templateId}`;
-      owner.register(templateFullName, template);
-
-      let outletState = {
-        render: {
-          owner,
-          into: undefined,
-          outlet: 'main',
-          name: 'application',
-          controller: undefined,
-          ViewClass: undefined,
-          template: owner.lookup('template:-outlet'),
-        },
-
-        outlets: {
-          main: {
-            render: {
-              owner,
-              into: undefined,
-              outlet: 'main',
-              name: 'index',
-              controller: context,
-              ViewClass: undefined,
-              template: owner.lookup(templateFullName),
-              outlets: {},
-            },
-            outlets: {},
-          },
-        },
-      };
-      toplevelView.setOutletState(outletState);
-
-      return settled();
-    }
-
-    module('setupRenderingContext', function (hooks) {
-      hooks.beforeEach(async function () {
-        expectDeprecation(
-          /The `template` property of `OutletState` should be a `Template` rather than a `TemplateFactory`/
-        );
-
-        this.application = Application.create({
-          rootElement: '#qunit-fixture',
-          autoboot: false,
-          Resolver: ModuleBasedTestResolver,
-        });
-
-        await setupContext(this);
-        await setupRenderingContext(this);
-      });
-
-      hooks.afterEach(function () {
-        run(this.owner, 'destroy');
-        run(this.application, 'destroy');
-      });
-
-      test('it basically works', async function (assert) {
-        await render(compile('Hi!'), this);
-
-        assert.equal(this.element.textContent, 'Hi!');
-      });
-    });
-  });
 });
diff --git a/tests/node/helpers/setup-component.js b/tests/node/helpers/setup-component.js
index 174c75c0b54..7f21d180a50 100644
--- a/tests/node/helpers/setup-component.js
+++ b/tests/node/helpers/setup-component.js
@@ -53,8 +53,6 @@ function setupComponentTest() {
   this._outletState = {
     render: {
       owner: module.owner || undefined,
-      into: undefined,
-      outlet: 'main',
       name: 'application',
       controller: module,
       model: undefined,
@@ -83,8 +81,6 @@ function render(_template) {
 
   let stateToRender = {
     owner: this.owner,
-    into: undefined,
-    outlet: 'main',
     name: 'index',
     controller: this,
     model: undefined,