diff --git a/Installation/CHANGES.md b/Installation/CHANGES.md
index ed91c406088..3f543f9e958 100644
--- a/Installation/CHANGES.md
+++ b/Installation/CHANGES.md
@@ -14,6 +14,15 @@ Release date: June 2021
 
 A comprehensive list of the supported file formats is available in the Stream_support package [here](https://doc.cgal.org/5.3/Stream_support/index.html#IOstreamSupportedFormats); inversely, the following [page](https://doc.cgal.org/5.3/Stream_support/IOStreamSupportedFileFormats.html) can be used to find out which CGAL data structures can be used given a specific file format.
 
+### [Quadtree, Octree and Orthtree](https://doc.cgal.org/5.3/Manual/packages.html#PkgOrthree) (new package)
+
+-   This package implements a tree data structure in which each node
+    encloses a hypercubic section of space and each non-leave node has
+    hypercubic children whose edge lengths are half its edge
+    length. Such a data structure is known as a quadtree in 2D, an
+    octree in 3D and is generalized as an "orthtree" in higher
+    dimensions.
+
 ### [Polygon Mesh Processing](https://doc.cgal.org/5.3/Manual/packages.html#PkgPolygonMeshProcessing)
 
 -   Added the class `CGAL::Polyhedral_envelope` providing a way to quickly check if a primitive (point, segment, or triangle)