diff --git a/src/wp-admin/js/customize-nav-menus.js b/src/wp-admin/js/customize-nav-menus.js
index cf7b9b1c2a..3e223825c4 100644
--- a/src/wp-admin/js/customize-nav-menus.js
+++ b/src/wp-admin/js/customize-nav-menus.js
@@ -1161,6 +1161,48 @@
 		}
 	});
 
+	/**
+	 * Create a nav menu setting and section.
+	 *
+	 * @since 4.9.0
+	 *
+	 * @param {string} [name=''] Nav menu name.
+	 * @returns {wp.customize.Menus.MenuSection} Added nav menu.
+	 */
+	api.Menus.createNavMenu = function createNavMenu( name ) {
+		var customizeId, placeholderId, setting;
+		placeholderId = api.Menus.generatePlaceholderAutoIncrementId();
+
+		customizeId = 'nav_menu[' + String( placeholderId ) + ']';
+
+		// Register the menu control setting.
+		setting = api.create( customizeId, customizeId, {}, {
+			type: 'nav_menu',
+			transport: api.Menus.data.settingTransport,
+			previewer: api.previewer
+		} );
+		setting.set( $.extend(
+			{},
+			api.Menus.data.defaultSettingValues.nav_menu,
+			{
+				name: name || ''
+			}
+		) );
+
+		/*
+		 * Add the menu section (and its controls).
+		 * Note that this will automatically create the required controls
+		 * inside via the Section's ready method.
+		 */
+		return api.section.add( new api.Menus.MenuSection( customizeId, {
+			panel: 'nav_menus',
+			title: displayNavMenuName( name ),
+			customizeAction: api.Menus.data.l10n.customizingMenus,
+			priority: 10,
+			menu_id: placeholderId
+		} ) );
+	};
+
 	/**
 	 * wp.customize.Menus.NewMenuSection
 	 *
@@ -1339,10 +1381,7 @@
 				contentContainer = section.contentContainer,
 				nameInput = contentContainer.find( '.menu-name-field' ).first(),
 				name = nameInput.val(),
-				menuSection,
-				customizeId,
-				editMenuSection,
-				placeholderId = api.Menus.generatePlaceholderAutoIncrementId();
+				menuSection;
 
 			if ( ! name ) {
 				nameInput.addClass( 'invalid' );
@@ -1350,35 +1389,7 @@
 				return;
 			}
 
-			customizeId = 'nav_menu[' + String( placeholderId ) + ']';
-
-			// Register the menu control setting.
-			api.create( customizeId, customizeId, {}, {
-				type: 'nav_menu',
-				transport: api.Menus.data.settingTransport,
-				previewer: api.previewer
-			} );
-			api( customizeId ).set( $.extend(
-				{},
-				api.Menus.data.defaultSettingValues.nav_menu,
-				{
-					name: name
-				}
-			) );
-
-			/*
-			 * Add the menu section (and its controls).
-			 * Note that this will automatically create the required controls
-			 * inside via the Section's ready method.
-			 */
-			menuSection = new api.Menus.MenuSection( customizeId, {
-				panel: 'nav_menus',
-				title: displayNavMenuName( name ),
-				customizeAction: api.Menus.data.l10n.customizingMenus,
-				priority: 10,
-				menu_id: placeholderId
-			} );
-			api.section.add( customizeId, menuSection );
+			menuSection = api.Menus.createNavMenu( name );
 
 			// Clear name field.
 			nameInput.val( '' );
@@ -1390,7 +1401,7 @@
 
 				if ( checkbox.prop( 'checked' ) ) {
 					navMenuLocationSetting = api( 'nav_menu_locations[' + checkbox.data( 'location-id' ) + ']' );
-					navMenuLocationSetting.set( placeholderId );
+					navMenuLocationSetting.set( menuSection.params.menu_id );
 
 					// Reset state for next new menu
 					checkbox.prop( 'checked', false );
@@ -1400,12 +1411,11 @@
 			wp.a11y.speak( api.Menus.data.l10n.menuAdded );
 
 			// Focus on the new menu section.
-			editMenuSection = api.section( customizeId );
-			editMenuSection.focus( {
+			menuSection.focus( {
 				completeCallback: function() {
-					editMenuSection.highlightNewItemButton();
+					menuSection.highlightNewItemButton();
 				}
-			} ); // @todo should we focus on the new menu's control and open the add-items panel? Thinking user flow...
+			} );
 		},
 
 		/**
@@ -3007,6 +3017,87 @@
 		}
 	} );
 
+	/**
+	 * wp.customize.Menus.NewMenuControl
+	 *
+	 * Customizer control for creating new menus and handling deletion of existing menus.
+	 * Note that 'new_menu' must match the WP_Customize_New_Menu_Control::$type.
+	 *
+	 * @constructor
+	 * @augments wp.customize.Control
+	 * @deprecated 4.9.0 This class is no longer used due to new menu creation UX.
+	 */
+	api.Menus.NewMenuControl = api.Control.extend({
+
+		/**
+		 * Initialize.
+		 *
+		 * @deprecated 4.9.0
+		 */
+		initialize: function() {
+			if ( 'undefined' !== typeof console && console.warn ) {
+				console.warn( '[DEPRECATED] wp.customize.NewMenuControl will be removed. Please use wp.customize.Menus.createNavMenu() instead.' );
+			}
+			api.Control.prototype.initialize.apply( this, arguments );
+		},
+
+		/**
+		 * Set up the control.
+		 *
+		 * @deprecated 4.9.0
+		 */
+		ready: function() {
+			this._bindHandlers();
+		},
+
+		_bindHandlers: function() {
+			var self = this,
+				name = $( '#customize-control-new_menu_name input' ),
+				submit = $( '#create-new-menu-submit' );
+			name.on( 'keydown', function( event ) {
+				if ( 13 === event.which ) { // Enter.
+					self.submit();
+				}
+			} );
+			submit.on( 'click', function( event ) {
+				self.submit();
+				event.stopPropagation();
+				event.preventDefault();
+			} );
+		},
+
+		/**
+		 * Create the new menu with the name supplied.
+		 *
+		 * @deprecated 4.9.0
+		 */
+		submit: function() {
+
+			var control = this,
+				container = control.container.closest( '.accordion-section-new-menu' ),
+				nameInput = container.find( '.menu-name-field' ).first(),
+				name = nameInput.val(),
+				menuSection;
+
+			if ( ! name ) {
+				nameInput.addClass( 'invalid' );
+				nameInput.focus();
+				return;
+			}
+
+			menuSection = api.Menus.createNavMenu( name );
+
+			// Clear name field.
+			nameInput.val( '' );
+			nameInput.removeClass( 'invalid' );
+
+			wp.a11y.speak( api.Menus.data.l10n.menuAdded );
+
+			// Focus on the new menu section.
+			menuSection.focus();
+		}
+	});
+
 	/**
 	 * Extends wp.customize.controlConstructor with control constructor for
 	 * menu_location, menu_item, nav_menu, and new_menu.
@@ -3016,6 +3107,7 @@
 		nav_menu_item: api.Menus.MenuItemControl,
 		nav_menu: api.Menus.MenuControl,
 		nav_menu_name: api.Menus.MenuNameControl,
+		new_menu: api.Menus.NewMenuControl, // @todo Remove in 5.0. See #42364.
 		nav_menu_locations: api.Menus.MenuLocationsControl,
 		nav_menu_auto_add: api.Menus.MenuAutoAddControl
 	});
diff --git a/src/wp-includes/class-wp-customize-control.php b/src/wp-includes/class-wp-customize-control.php
index 848608139d..4f289cd6e6 100644
--- a/src/wp-includes/class-wp-customize-control.php
+++ b/src/wp-includes/class-wp-customize-control.php
@@ -769,6 +769,12 @@ require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-location
 
 /**
  * WP_Customize_Nav_Menu_Name_Control class.
+ *
+ * As this file is deprecated, it will trigger a deprecation notice if instantiated. In a subsequent
+ * release, the require_once() here will be removed and _deprecated_file() will be called if file is
+ * required at all.
+ *
+ * @deprecated 4.9.0 This file is no longer used due to new menu creation UX.
  */
 require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-name-control.php' );
 
diff --git a/src/wp-includes/class-wp-customize-manager.php b/src/wp-includes/class-wp-customize-manager.php
index ba2a543312..18be7964b0 100644
--- a/src/wp-includes/class-wp-customize-manager.php
+++ b/src/wp-includes/class-wp-customize-manager.php
@@ -317,6 +317,7 @@ final class WP_Customize_Manager {
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-name-control.php' );
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-locations-control.php' );
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-auto-add-control.php' );
+		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-new-menu-control.php' ); // @todo Remove in 5.0. See #42364.
 
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menus-panel.php' );
 
@@ -324,6 +325,7 @@ final class WP_Customize_Manager {
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-themes-section.php' );
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-sidebar-section.php' );
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-section.php' );
+		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-new-menu-section.php' ); // @todo Remove in 5.0. See #42364.
 
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-custom-css-setting.php' );
 		require_once( ABSPATH . WPINC . '/customize/class-wp-customize-filter-setting.php' );
diff --git a/src/wp-includes/class-wp-customize-section.php b/src/wp-includes/class-wp-customize-section.php
index f4a0d20113..a4a6074afb 100644
--- a/src/wp-includes/class-wp-customize-section.php
+++ b/src/wp-includes/class-wp-customize-section.php
@@ -385,3 +385,14 @@ require_once( ABSPATH . WPINC . '/customize/class-wp-customize-sidebar-section.p
 
 /** WP_Customize_Nav_Menu_Section class */
 require_once( ABSPATH . WPINC . '/customize/class-wp-customize-nav-menu-section.php' );
+
+/**
+ * WP_Customize_New_Menu_Section class
+ *
+ * As this file is deprecated, it will trigger a deprecation notice if instantiated. In a subsequent
+ * release, the require_once() here will be removed and _deprecated_file() will be called if file is
+ * required at all.
+ *
+ * @deprecated 4.9.0 This file is no longer used due to new menu creation UX.
+ */
+require_once( ABSPATH . WPINC . '/customize/class-wp-customize-new-menu-section.php' );
diff --git a/src/wp-includes/customize/class-wp-customize-new-menu-control.php b/src/wp-includes/customize/class-wp-customize-new-menu-control.php
index 24bcb1ea88..9925b59bff 100644
--- a/src/wp-includes/customize/class-wp-customize-new-menu-control.php
+++ b/src/wp-includes/customize/class-wp-customize-new-menu-control.php
@@ -5,12 +5,14 @@
  * @package WordPress
  * @subpackage Customize
  * @since 4.4.0
+ * @deprecated 4.9.0 This file is no longer used as of the menu creation UX introduced in #40104.
  */
 
 /**
  * Customize control class for new menus.
  *
  * @since 4.3.0
+ * @deprecated 4.9.0 This class is no longer used as of the menu creation UX introduced in #40104.
  *
  * @see WP_Customize_Control
  */
@@ -24,6 +26,20 @@ class WP_Customize_New_Menu_Control extends WP_Customize_Control {
 	 */
 	public $type = 'new_menu';
 
+	/**
+	 * Constructor.
+	 *
+	 * @since 4.9.0
+	 *
+	 * @param WP_Customize_Manager $manager Manager.
+	 * @param string               $id      ID.
+	 * @param array                $args    Args.
+	 */
+	public function __construct( WP_Customize_Manager $manager, $id, array $args = array() ) {
+		_deprecated_file( basename( __FILE__ ), '4.9.0' ); // @todo Move this outside of class in 5.0, and remove its require_once() from class-wp-customize-control.php. See #42364.
+		parent::__construct( $manager, $id, $args );
+	}
+
 	/**
 	 * Render the control's content.
 	 *
diff --git a/src/wp-includes/customize/class-wp-customize-new-menu-section.php b/src/wp-includes/customize/class-wp-customize-new-menu-section.php
index 12723183c9..e0b9b0c5ad 100644
--- a/src/wp-includes/customize/class-wp-customize-new-menu-section.php
+++ b/src/wp-includes/customize/class-wp-customize-new-menu-section.php
@@ -5,14 +5,14 @@
  * @package WordPress
  * @subpackage Customize
  * @since 4.4.0
+ * @deprecated 4.9.0 This file is no longer used as of the menu creation UX introduced in #40104.
  */
 
 /**
  * Customize Menu Section Class
  *
- * Implements the new-menu-ui toggle button instead of a regular section.
- *
  * @since 4.3.0
+ * @deprecated 4.9.0 This class is no longer used as of the menu creation UX introduced in #40104.
  *
  * @see WP_Customize_Section
  */
@@ -26,6 +26,22 @@ class WP_Customize_New_Menu_Section extends WP_Customize_Section {
 	 */
 	public $type = 'new_menu';
 
+	/**
+	 * Constructor.
+	 *
+	 * Any supplied $args override class property defaults.
+	 *
+	 * @since 4.9.0
+	 *
+	 * @param WP_Customize_Manager $manager Customizer bootstrap instance.
+	 * @param string               $id      An specific ID of the section.
+	 * @param array                $args    Section arguments.
+	 */
+	public function __construct( WP_Customize_Manager $manager, $id, array $args = array() ) {
+		_deprecated_file( basename( __FILE__ ), '4.9.0' ); // @todo Move this outside of class in 5.0, and remove its require_once() from class-wp-customize-section.php. See #42364.
+		parent::__construct( $manager, $id, $args );
+	}
+
 	/**
 	 * Render the section, and the controls that have been added to it.
 	 *
diff --git a/tests/qunit/wp-admin/js/customize-nav-menus.js b/tests/qunit/wp-admin/js/customize-nav-menus.js
index 9b60272875..3ac6da8662 100644
--- a/tests/qunit/wp-admin/js/customize-nav-menus.js
+++ b/tests/qunit/wp-admin/js/customize-nav-menus.js
@@ -113,9 +113,9 @@ jQuery( window ).load( function (){
 	// @todo Add tests for api.Menus.MenuLocationsControl
 	// @todo Add tests for api.Menus.MenuAutoAddControl
 	// @todo Add tests for api.Menus.MenuControl
-	// @todo Add tests for api.Menus.NewMenuControl
 	// @todo Add tests for api.Menus.applySavedData
 	// @todo Add tests for api.Menus.focusMenuItemControl
+	// @todo Add tests for api.Menus.createNavMenu
 
 	test( 'api.Menus.getMenuControl() should return the expected control', function() {
 		var control = api.Menus.getMenuControl( primaryMenuId );