diff --git a/Help/release/dev/find-modules.rst b/Help/release/dev/find-modules.rst
index c95384cf7a..3cbcc7c7b9 100644
--- a/Help/release/dev/find-modules.rst
+++ b/Help/release/dev/find-modules.rst
@@ -34,6 +34,9 @@ Find Modules
 * The :module:`FindGnuTLS` module now provides a ``GnuTLS_VERSION`` result
   variable.  The ``GNUTLS_VERSION`` result variable is deprecated.
 
+* The :module:`FindHg` module now provides a ``Hg_VERSION`` result
+  variable.  The ``HG_VERSION_STRING`` result variable is deprecated.
+
 * The :module:`FindJasper` module now provides a ``Jasper_VERSION`` result
   variable.  The ``JASPER_VERSION_STRING`` result variable is deprecated.
 
diff --git a/Modules/ExternalProject/shared_internal_commands.cmake b/Modules/ExternalProject/shared_internal_commands.cmake
index c2e5b47214..df1290ee70 100644
--- a/Modules/ExternalProject/shared_internal_commands.cmake
+++ b/Modules/ExternalProject/shared_internal_commands.cmake
@@ -1596,7 +1596,7 @@ function(_ep_add_update_command name)
       set(hg_tag "tip")
     endif()
 
-    if("${HG_VERSION_STRING}" STREQUAL "2.1")
+    if("${Hg_VERSION}" STREQUAL "2.1")
       set(notesAnchor
         "#A2.1.1:_revert_pull_return_code_change.2C_compile_issue_on_OS_X"
       )
diff --git a/Modules/FindHg.cmake b/Modules/FindHg.cmake
index f4f30743da..1c04f0b788 100644
--- a/Modules/FindHg.cmake
+++ b/Modules/FindHg.cmake
@@ -22,7 +22,9 @@ This module defines the following variables:
   found.  For backward compatibility, the ``HG_FOUND`` variable is also set
   to the same value.
 
-``HG_VERSION_STRING``
+``Hg_VERSION``
+  .. versionadded:: 4.2
+
   The version of Mercurial found.
 
 Cache Variables
@@ -58,6 +60,15 @@ found:
   ``<var-prefix>_WC_REVISION``
     Current revision.
 
+Deprecated Variables
+^^^^^^^^^^^^^^^^^^^^
+
+The following variables are provided for backward compatibility:
+
+``HG_VERSION_STRING``
+  .. deprecated:: 4.2
+    Use ``Hg_VERSION``, which has the same value.
+
 Examples
 ^^^^^^^^
 
@@ -103,7 +114,8 @@ if(HG_EXECUTABLE)
     set_property(CACHE HG_EXECUTABLE PROPERTY VALUE "HG_EXECUTABLE-NOTFOUND")
   endif()
   if(hg_version MATCHES "^Mercurial Distributed SCM \\(version ([0-9][^)]*)\\)")
-    set(HG_VERSION_STRING "${CMAKE_MATCH_1}")
+    set(Hg_VERSION "${CMAKE_MATCH_1}")
+    set(HG_VERSION_STRING "${Hg_VERSION}")
   endif()
   unset(hg_version)
 
@@ -126,4 +138,4 @@ endif()
 include(FindPackageHandleStandardArgs)
 find_package_handle_standard_args(Hg
                                   REQUIRED_VARS HG_EXECUTABLE
-                                  VERSION_VAR HG_VERSION_STRING)
+                                  VERSION_VAR Hg_VERSION)
diff --git a/Tests/CMakeOnly/AllFindModules/CMakeLists.txt b/Tests/CMakeOnly/AllFindModules/CMakeLists.txt
index a95fc982b2..c6c032aea2 100644
--- a/Tests/CMakeOnly/AllFindModules/CMakeLists.txt
+++ b/Tests/CMakeOnly/AllFindModules/CMakeLists.txt
@@ -119,7 +119,7 @@ foreach(
     EXPAT
     FLEX Freetype
     Gettext GIF GnuTLS GNUTLS GTK2
-    HDF5
+    HDF5 Hg
     Jasper JPEG
     LibArchive LibLZMA LIBLZMA LibXml2 LibXslt LTTngUST
     OpenSceneGraph OPENSCENEGRAPH OpenSSL OPENSSL
diff --git a/Tests/ExternalProject/CMakeLists.txt b/Tests/ExternalProject/CMakeLists.txt
index 12081522ac..b1ce43a215 100644
--- a/Tests/ExternalProject/CMakeLists.txt
+++ b/Tests/ExternalProject/CMakeLists.txt
@@ -595,7 +595,7 @@ if(EP_TEST_HG)
   #
   # Mercurial 2.1 does not distinguish an empty pull from a failed pull,
   # so do not run the test with that version.
-  if(NOT "${HG_VERSION_STRING}" STREQUAL "2.1")
+  if(NOT Hg_VERSION STREQUAL "2.1")
     set(proj TutorialStep1-HG-tip)
     ExternalProject_Add(${proj}
       HG_REPOSITORY "${local_hg_repo}"