diff --git a/actionpack/CHANGELOG.md b/actionpack/CHANGELOG.md
index 1218e07372702..89dbcf7d458a4 100644
--- a/actionpack/CHANGELOG.md
+++ b/actionpack/CHANGELOG.md
@@ -1,3 +1,7 @@
+*   Remove deprecated support to define routes with `:to` option that doesn't contain `#`.
+
+    *Rafael Mendonça França*
+
 *   Remove deprecated `ActionDispatch::Response#to_ary`.
 
     *Rafael Mendonça França*
diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index b9e916078cc26..e793ef849e013 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -8,7 +8,6 @@
 require 'active_support/inflector'
 require 'action_dispatch/routing/redirection'
 require 'action_dispatch/routing/endpoint'
-require 'active_support/deprecation'
 
 module ActionDispatch
   module Routing
@@ -279,22 +278,8 @@ def check_part(name, part, path_params, hash)
           end
 
           def split_to(to)
-            case to
-            when Symbol
-              ActiveSupport::Deprecation.warn(<<-MSG.squish)
-                Defining a route where `to` is a symbol is deprecated.
-                Please change `to: :#{to}` to `action: :#{to}`.
-              MSG
-
-              [nil, to.to_s]
-            when /#/    then to.split('#')
-            when String
-              ActiveSupport::Deprecation.warn(<<-MSG.squish)
-                Defining a route where `to` is a controller without an action is deprecated.
-                Please change `to: :#{to}` to `controller: :#{to}`.
-              MSG
-
-              [to, nil]
+            if to =~ /#/
+              to.split('#')
             else
               []
             end
diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
index aae95fb355262..450681c356659 100644
--- a/actionpack/test/dispatch/routing_test.rb
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -3331,30 +3331,6 @@ def test_mix_string_to_action
     assert_equal 'comments#index', @response.body
   end
 
-  def test_mix_symbol_to_controller_action
-    assert_deprecated do
-      draw do
-        get '/projects', controller: 'project_files',
-                         action: 'index',
-                         to: :show
-      end
-    end
-    get '/projects'
-    assert_equal 'project_files#show', @response.body
-  end
-
-  def test_mix_string_to_controller_action_no_hash
-    assert_deprecated do
-      draw do
-        get '/projects', controller: 'project_files',
-                         action: 'index',
-                         to: 'show'
-      end
-    end
-    get '/projects'
-    assert_equal 'show#index', @response.body
-  end
-
   def test_shallow_path_and_prefix_are_not_added_to_non_shallow_routes
     draw do
       scope shallow_path: 'projects', shallow_prefix: 'project' do
@@ -3629,15 +3605,13 @@ def test_missing_controller
     assert_match(/Missing :controller/, ex.message)
   end
 
-  def test_missing_action
+  def test_missing_controller_with_to
     ex = assert_raises(ArgumentError) {
-      assert_deprecated do
-        draw do
-          get '/foo/bar', :to => 'foo'
-        end
+      draw do
+        get '/foo/bar', :to => 'foo'
       end
     }
-    assert_match(/Missing :action/, ex.message)
+    assert_match(/Missing :controller/, ex.message)
   end
 
   def test_missing_action_on_hash