When hiring an attorney to represent you in immigration law matters, the usual advice about making sure he or she is a member in good standing of your state bar association does not apply – at least, not with respect to the word "your."
Immigration law is federal, and is administered through a federal agency (the Department of Homeland Security). Once a lawyer has been licensed by the bar association of one or more states, and learned the basics of immigration law, the lawyer can set up practice wherever he or she chooses – in any U.S. state, or even in another country.
The immigration authorities recognize this fact, and regardless of which U.S. state the office or immigration court the immigrant applicant will be interacting with is located, accept representation by lawyers who are members of the bar in different states. Many attorneys end up practicing far from the state where they were originally licensed. And even if they remain in the same state, they may accept clients from other states or countries.
Note, however, that some differences in interpretation of immigration law exist between the various federal circuits. (The U.S. federal courts are divided into 13 "circuits," based on region; and many immigration matters can be appealed to those courts.) The immigration authorities must follow their local circuit court's interpretations. This can affect both everyday administrative matters as well as issues that come up in deportation or removal proceedings. Therefore, it can be helpful to hire a lawyer who has been practicing for some years in the area where your immigration case will be decided upon.
Also, if you will be asking the immigration lawyer to interpret how a state crime will be viewed under the immigration laws, that attorney needs to be a bar member in the state where the crime and conviction took place. (A responsible immigration attorney will bring in another local attorney as a consultant in such a situation.)
But there are some important caveats to this advice, as follows.
And of course, for convenience sake, you probably want to hire an attorney who is practicing in the area where you will be attending your immigration interviews or hearings, so that you can have your attorney present without paying for plane tickets!