You could cookie them. Issues you may run into: users with ad-blocking software may reject the cookie altogether, but they may also be familiar with that pitfall. Users may also manually clear cache/cookies and not benefit. Another caveat is if you use caching, cookies can be a bit tricky to get working reliably. Finally, depending on whether you have any EU users, you may also need extra data security and privacy policy info (and have to have your users opt in to cookies) so that may be a sticky situation.
I’d suggest putting a login form in top navigation instead. This way you can help any user from any page quickly log in. No matter where they land, and no matter whether they can be cookied reliably, they can still get to that form and jump to their desired content. You can include a parameter in the form that redirects them immediately to a specific landing page upon successful login, if you like.