diff --git a/django/contrib/auth/models.py b/django/contrib/auth/models.py
index 00a6f0b097..40037b96b4 100644
--- a/django/contrib/auth/models.py
+++ b/django/contrib/auth/models.py
@@ -4,8 +4,6 @@ from django.contrib.contenttypes.models import ContentType
 from django.utils.translation import gettext_lazy as _
 import datetime
 
-SESSION_KEY = '_auth_user_id'
-
 def check_password(raw_password, enc_password):
     """
     Returns a boolean of whether the raw_password was correct. Handles