In general, as Ailfertes states, the ancient sources, particularly Strabo and Pliny, are an excellent starting point. In terms of the Geographical data, these can be supplemented with modern climatological data, for which I usually start with wikipedia: obviously, it should be noted if there were major climatic shifts. For the historical section we are really after an overview of socio-political development in that specific region - again ancient sources are useful, and should be at least examined, but using a entry-level, more general, history to begin is great.
If you have access to JSTOR, I would guess that you are either a secondary, tertiary or postgrad student. As such you may have access to such resources as Brill's New Pauly - which, usually, has accurate scholarly encyclopedia articles on a wide-range of subjects including regions.
I hope this is helpful - and not overwhelming.
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