diff --git a/docs/ref/contrib/postgres/fields.txt b/docs/ref/contrib/postgres/fields.txt
index 80b63b9..5073142 100644
--- a/docs/ref/contrib/postgres/fields.txt
+++ b/docs/ref/contrib/postgres/fields.txt
@@ -588,6 +588,12 @@ All of the range fields translate to :ref:`psycopg2 Range objects
 information is necessary. The default is lower bound included, upper bound
 excluded.
 
+.. note::
+
+    The PostgreSQL ``DateRangeField`` will always return a canonicalized
+    form that includes the lower bound and excludes the upper bound; that is, ``[)``.
+
+
 ``IntegerRangeField``
 ---------------------