diff --git a/django/contrib/sites/management.py b/django/contrib/sites/management.py
index 975bafe1ff..a9daf1cc75 100644
--- a/django/contrib/sites/management.py
+++ b/django/contrib/sites/management.py
@@ -3,6 +3,7 @@ Creates the default Site object.
 """
 
 from django.apps import apps
+from django.conf import settings
 from django.core.management.color import no_style
 from django.db import DEFAULT_DB_ALIAS, connections, router
 
@@ -24,7 +25,7 @@ def create_default_site(app_config, verbosity=2, interactive=True, db=DEFAULT_DB
         # can also crop up outside of tests - see #15346.
         if verbosity >= 2:
             print("Creating example.com Site object")
-        Site(pk=1, domain="example.com", name="example.com").save(using=db)
+        Site(pk=settings.SITE_ID, domain="example.com", name="example.com").save(using=db)
 
         # We set an explicit pk instead of relying on auto-incrementation,
         # so we need to reset the database sequence. See #17415.
diff --git a/django/contrib/sites/tests.py b/django/contrib/sites/tests.py
index 5b6b1fc4a8..72c7a9f8c7 100644
--- a/django/contrib/sites/tests.py
+++ b/django/contrib/sites/tests.py
@@ -176,6 +176,14 @@ class CreateDefaultSiteTests(TestCase):
         post_migrate.send(sender=self.app_config, app_config=self.app_config, verbosity=0)
         self.assertTrue(Site.objects.exists())
 
+    @override_settings(SITE_ID=35696)
+    def test_custom_site_id(self):
+        """
+        #23945 - The configured ``SITE_ID`` should be respected.
+        """
+        create_default_site(self.app_config, verbosity=0)
+        self.assertEqual(Site.objects.get().pk, 35696)
+
 
 class MiddlewareTest(TestCase):
 
diff --git a/docs/releases/1.8.txt b/docs/releases/1.8.txt
index f96067fa81..4afa02dd18 100644
--- a/docs/releases/1.8.txt
+++ b/docs/releases/1.8.txt
@@ -168,6 +168,10 @@ Minor features
   <django.http.HttpRequest.get_host>` if the :setting:`SITE_ID` setting is not
   defined.
 
+* The default :class:`~django.contrib.sites.models.Site` created when running
+  ``migrate`` now respects the :setting:`SITE_ID` setting (instead of always
+  using ``pk=1``).
+
 :mod:`django.contrib.staticfiles`
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^