diff --git a/documentation/ref-manual/classes.rst b/documentation/ref-manual/classes.rst
index 2fa888e15..acdbe9935 100644
--- a/documentation/ref-manual/classes.rst
+++ b/documentation/ref-manual/classes.rst
@@ -476,6 +476,10 @@ build configuration system. "cml" stands for "Configuration Menu Language", whic
 originates from the Linux kernel but is also used in other projects such as U-Boot
 and BusyBox. It could have been called "kconfig" too.
 
+The CML configuration file location (``.config``) is by default expected to be
+in the build directory (:term:`B`). This can be overridden with the
+:term:`KCONFIG_CONFIG_ROOTDIR` variable.
+
 .. _ref-classes-compress_doc:
 
 ``compress_doc``
diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index 60e608c0c..20e4893d6 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -5337,6 +5337,11 @@ system and gives an overview of their function and contents.
       :yocto_git:`symbol_why.py </yocto-kernel-tools/tree/tools/symbol_why.py>`
       script in :yocto_git:`yocto-kernel-tools </yocto-kernel-tools>`.
 
+   :term:`KCONFIG_CONFIG_ROOTDIR`
+      The :term:`KCONFIG_CONFIG_ROOTDIR` variable allows overriding the default
+      location of the ``.config`` file for recipes using the
+      :ref:`ref-classes-cml1` class.
+
    :term:`KCONFIG_MODE`
       When used with the :ref:`ref-classes-kernel-yocto`
       class, specifies the kernel configuration values to use for options
