When looking for a merchant account provider, is it necessary to do business with one that is local...? I have been helping merchants with credit card processing services for over five years now and my answer to this question is:
 
"No."

Not in this day age.  At one time, yes this was important because a werprovider couldn't support merchants who e not close by.   But now when something goes wrong with your POS terminal and it is determined that it can not be fixed over the phone, companies just ship a brand new debit machine and wait for the broken unit to be shipped back to do the repair on the card processor's own time. This is great because merchants get new terminal within 24 hours or quicker and have very little downtime.

When I first started in this industry, they used to send out technicians, but it caused more wait time for Merchants, it's better for everyone just to ship out brand new Debit Machines out as need be.  And most companies follow this procedure.  If they do not, you may want to reconsider doing business with them, otherwise, then in that scenario you will want to make sure the service provider is local.