You should check with an experienced attorney in the State where you are seeking a pardon. I cannot imagine that residency would bar an application for a pardon, but the best way to find out is to inquire with the particular State
I am pleased to communicate with you concerning legal matters. However, if you communicate with me through this website regarding a matter for which my firm DOES NOT ALREADY REPRESENT YOU, your communication may NOT be treated as privileged or confidential, and shall NOT be deemed to create an attorney/client relationship. Furthermore, you should NOT provide confidential information to my law firm in an e-mail inquiry or otherwise unless we have FIRST entered into a representation agreement.
Yes, you can get a pardon in another state even if you do not live there anymore. You should contact an attorney in that state. If it was a state other than Maryland, you could consider posting in the AVVO forum for that state. Every state's laws are different.