This section of the forum is for discussing the business and finance issues of the t-shirt industry. Which business structure to use (sole proprietor, LLC, S Corp, etc), how to handle billing, where to register your business and get the proper licensing, etc.
OK the name of my brand is Entropy, and I've seen 3 brands on the trademark search with that name. I'm based out of Puerto Rico, and plan to stay locally for the foreseeable future,and they also appear to be located in Calif, Jersey and forgot the state, would I have trademark issues? Mind you i've been using that logo before I even decided to pursue a clothing brand so I didn't do it out of malice. If anyone can answer I'd be more than welcome.
If you are looking up the marks on the USPTO website, the state doesn't matter, they are federal registrations. You need to verify if the marks or Live or Dead and the Class the marks are registered for. That will give you some info to help make your decision.
But to be honest, since you have identified potential issues, you really need professional legal advice from an intellectual property attorney. Nothing that gets said on a free forum will truly give you the answer you need.
Mind you i've been using that logo before I even decided to pursue a clothing brand
That doesn't matter. The whole point of having a federal registration program is to avoid such conflicts.
You can stay local and keep using your mark. You won't have a problem until someone tries to enforce the mark. Like kimura-mma said, check whether the mark is dead or live and the class of registration.
Trademark Question 
