From an Atlantic perspective, our core is very small so the best answer is probably yes it's all in the same district. Your impression would probably be everything except suburban malls and car dealerships is in that one core district.
But within that, there is one particular strip - George Street - that has most of our main bars for young people, old people, live music, karaoke, folk music, dance music, etc.
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And most neighbourhoods have a shitty little local. Mine, for example, is the Peter Easton:
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