I got put on unsupervised probation for 4 months for misdeameanor possession and it ends in march but I will be leaving for college in January to a different state. Do I have to tell someone that I'm leaving or can I just leave and not get into any trouble?

You must discuss this with your PO as soon as possible and see what they want to do with your probation. Don't just leave out of state without their written permission or you will be violated.

No you can not "just leave" if you don't have a contact number for the PO department contact the court and find out the contact. You really needed to address this with the court at sentecing. Since it can take time to get approval at time