Disabling Android Device Manager location notification on Galaxy S4
The "location accessed" notification comes from Google Play Services. (You can find out what app a notification comes from by long-pressing it and then selecting "app info.")

To disable notifications from Google Play Services, open Settings > Apps > All > Google Play Services, and then untick show notifications, then accept the prompt. 

Note: After disabling these notifications, you may not receive certain alerts from that app, like updating Google Play services.