diff --git a/docs/src/whatsnew/latest.rst b/docs/src/whatsnew/latest.rst
index 970ab979e8..d0364f5edf 100644
--- a/docs/src/whatsnew/latest.rst
+++ b/docs/src/whatsnew/latest.rst
@@ -185,6 +185,10 @@ This document explains the changes made to Iris for this release
    :func:`math.isclose`. The :func:`~iris.util.approx_equal` function will be
    removed in a future release of Iris. (:pull:`4514`)
 
+#. `@wjbenfold`_ deprecated :mod:`iris.experimental.raster` as it is not
+   believed to still be in use. The deprecation warnings invite users to contact
+   the Iris Developers if this isn't the case. (:pull:`4525`)
+
 
 🔗 Dependencies
 ===============
diff --git a/lib/iris/experimental/raster.py b/lib/iris/experimental/raster.py
index 83fd761973..f16dcbef5a 100644
--- a/lib/iris/experimental/raster.py
+++ b/lib/iris/experimental/raster.py
@@ -20,8 +20,17 @@
 from osgeo import gdal, osr
 
 import iris
+from iris._deprecation import warn_deprecated
 import iris.coord_systems
 
+wmsg = (
+    "iris.experimental.raster has been deprecated and will be removed in a "
+    "future release. If you make use of this functionality, please contact "
+    "the Iris Developers to discuss how to retain it (which may involve "
+    "reversing the deprecation)."
+)
+warn_deprecated(wmsg)
+
 _GDAL_DATATYPES = {
     "i2": gdal.GDT_Int16,
     "i4": gdal.GDT_Int32,