Some very successful firms that specialize in rural real estate would be good too
Real estate companies tend to not specialize in specific types of residential real estate, but individual agents do specialize in specific neighborhoods. You need to remember that Realtor's are licensed by the individual states do companies/offices tend to specialize in the location of their office. In addition I have found that while you may know the names of the larger franchised companies the real talent is completely found in the individual agent no matter what company they are associated with.
