diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index adc49c8929..a9d9285d42 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,13 @@
+*   Remove deprecated methods from `ActiveRecord::DatabaseConfigurations`.
+
+    `fetch`
+    `each`
+    `first`
+    `values`
+    `[]=`
+
+    *Rafael Mendonça França*
+
 *   `where.not` now generates NAND predicates instead of NOR.
 
      Before:
diff --git a/activerecord/lib/active_record/database_configurations.rb b/activerecord/lib/active_record/database_configurations.rb
index 807d164394..c33f33a75e 100644
--- a/activerecord/lib/active_record/database_configurations.rb
+++ b/activerecord/lib/active_record/database_configurations.rb
@@ -116,19 +116,6 @@ module ActiveRecord
     end
     alias :blank? :empty?
 
-    def each
-      throw_getter_deprecation(:each)
-      configurations.each { |config|
-        yield [config.env_name, config.configuration_hash]
-      }
-    end
-
-    def first
-      throw_getter_deprecation(:first)
-      config = configurations.first
-      [config.env_name, config.configuration_hash]
-    end
-
     # Returns fully resolved connection, accepts hash, string or symbol.
     # Always returns a DatabaseConfiguration::DatabaseConfig
     #
@@ -281,37 +268,5 @@ module ActiveRecord
         url ||= ENV["DATABASE_URL"] if name == "primary"
         url
       end
-
-      def method_missing(method, *args, &blk)
-        case method
-        when :fetch
-          throw_getter_deprecation(method)
-          configs_for(env_name: args.first)
-        when :values
-          throw_getter_deprecation(method)
-          configurations.map(&:configuration_hash)
-        when :[]=
-          throw_setter_deprecation(method)
-
-          env_name = args[0]
-          config = args[1]
-
-          remaining_configs = configurations.reject { |db_config| db_config.env_name == env_name }
-          new_config = build_configs(env_name => config)
-          new_configs = remaining_configs + new_config
-
-          ActiveRecord::Base.configurations = new_configs
-        else
-          raise NotImplementedError, "`ActiveRecord::Base.configurations` in Rails 6 now returns an object instead of a hash. The `#{method}` method is not supported. Please use `configs_for` or consult the documentation for supported methods."
-        end
-      end
-
-      def throw_setter_deprecation(method)
-        ActiveSupport::Deprecation.warn("Setting `ActiveRecord::Base.configurations` with `#{method}` is deprecated. Use `ActiveRecord::Base.configurations=` directly to set the configurations instead.")
-      end
-
-      def throw_getter_deprecation(method)
-        ActiveSupport::Deprecation.warn("`ActiveRecord::Base.configurations` no longer returns a hash. Methods that act on the hash like `#{method}` are deprecated and will be removed in Rails 6.1. Use the `configs_for` method to collect and iterate over the database configurations.")
-      end
   end
 end
diff --git a/activerecord/test/cases/database_configurations_test.rb b/activerecord/test/cases/database_configurations_test.rb
index fffa88183f..9e2bd5a165 100644
--- a/activerecord/test/cases/database_configurations_test.rb
+++ b/activerecord/test/cases/database_configurations_test.rb
@@ -108,22 +108,6 @@ class DatabaseConfigurationsTest < ActiveRecord::TestCase
 end
 
 class LegacyDatabaseConfigurationsTest < ActiveRecord::TestCase
-  unless in_memory_db?
-    def test_setting_configurations_hash
-      old_config = ActiveRecord::Base.configurations
-      config = { "adapter" => "sqlite3" }
-
-      assert_deprecated do
-        ActiveRecord::Base.configurations["readonly"] = config
-      end
-
-      assert_equal ["arunit", "arunit2", "arunit_without_prepared_statements", "readonly"], ActiveRecord::Base.configurations.configs_for.map(&:env_name).sort
-    ensure
-      ActiveRecord::Base.configurations = old_config
-      ActiveRecord::Base.establish_connection :arunit
-    end
-  end
-
   def test_can_turn_configurations_into_a_hash_and_is_deprecated
     assert_deprecated do
       assert ActiveRecord::Base.configurations.to_h.is_a?(Hash), "expected to be a hash but was not."
@@ -131,40 +115,6 @@ class LegacyDatabaseConfigurationsTest < ActiveRecord::TestCase
     end
   end
 
-  def test_each_is_deprecated
-    assert_deprecated do
-      all_configs = ActiveRecord::Base.configurations.values
-      ActiveRecord::Base.configurations.each do |env_name, config|
-        assert_includes ["arunit", "arunit2", "arunit_without_prepared_statements"], env_name
-        assert_includes all_configs, config
-      end
-    end
-  end
-
-  def test_first_is_deprecated
-    first_config = ActiveRecord::Base.configurations.configurations.map(&:configuration_hash).first
-    assert_deprecated do
-      env_name, config = ActiveRecord::Base.configurations.first
-      assert_equal "arunit", env_name
-      assert_equal first_config, config
-    end
-  end
-
-  def test_fetch_is_deprecated
-    assert_deprecated do
-      db_config = ActiveRecord::Base.configurations.fetch("arunit").first
-      assert_equal "arunit", db_config.env_name
-      assert_equal "primary", db_config.name
-    end
-  end
-
-  def test_values_are_deprecated
-    config_hashes = ActiveRecord::Base.configurations.configurations.map(&:configuration_hash)
-    assert_deprecated do
-      assert_equal config_hashes, ActiveRecord::Base.configurations.values
-    end
-  end
-
   def test_deprecated_config_method
     db_config = ActiveRecord::Base.configurations.configs_for(env_name: "arunit", name: "primary")
 
@@ -172,8 +122,8 @@ class LegacyDatabaseConfigurationsTest < ActiveRecord::TestCase
   end
 
   def test_unsupported_method_raises
-    assert_raises NotImplementedError do
-      ActiveRecord::Base.configurations.select { |a| a == "foo" }
+    assert_raises NoMethodError do
+      ActiveRecord::Base.configurations.fetch(:foo)
     end
   end
 
diff --git a/guides/source/6_1_release_notes.md b/guides/source/6_1_release_notes.md
index caae54a853..f575acd0e7 100644
--- a/guides/source/6_1_release_notes.md
+++ b/guides/source/6_1_release_notes.md
@@ -149,6 +149,14 @@ Please refer to the [Changelog][active-record] for detailed changes.
 
 ### Removals
 
+*   Remove deprecated methods from `ActiveRecord::DatabaseConfigurations`.
+
+    `fetch`
+    `each`
+    `first`
+    `values`
+    `[]=`
+
 *   Remove deprecated `ActiveRecord::Result#to_hash` method.
 
 *   Remove deprecated support for using unsafe raw SQL in `ActiveRecord::Relation` methods.