diff --git a/lib/matplotlib/widgets.py b/lib/matplotlib/widgets.py
index 2c395250b2e5..8b4055643a74 100644
--- a/lib/matplotlib/widgets.py
+++ b/lib/matplotlib/widgets.py
@@ -2334,6 +2334,13 @@ def _set_active_handle(self, event):
 
     @property
     def geometry(self):
+        """
+        Returns numpy.ndarray of shape (2,5) containing
+        x (``RectangleSelector.geometry[1,:]``) and
+        y (``RectangleSelector.geometry[0,:]``)
+        coordinates of the four corners of the rectangle starting
+        and ending in the top left corner.
+        """
         if hasattr(self.to_draw, 'get_verts'):
             xfm = self.ax.transData.inverted()
             y, x = xfm.transform(self.to_draw.get_verts()).T