I can see when a user has logged into NS by using the login audit trail. Is there a way to track how long a user stays logged in or better yet, when they log out or are force-logged out, such as with a time-out?

You could use Formula(Date Time) column to calculate the time between log in and log out.

@bharath64 so, my question is now 'Where can I find a reference to log out?' I would live a log out time, but I can't seem to find that stored anywhere?