You can have as many as location under one LLC and can maintain multiple businesses. If you collect sales tax from your customers then you have to notify to the concerned department to include this location under your existing sales tax vendor identification number.

You can operate multiple buisness locations (physical addresses) under the same EIN for a LLC, Corp, Etc. As long as you're using the same business name you're set. I would make sure you properly file state sales tax properly for both locations. I would suggest speaking with a professional tax attorney to have him make sure you're properly operating both locations tax wise.