Rann, as originally appearing in Showcase #17 (1958) is in the Alpha Centauri system. It's home to an advanced civilization reminiscent of advanced civilizations throughout planetary romance--which is to say advanced in some ways but without a lot of infrastructure to get in the way of adventuring. The person doing the adventuring in this case is Adam Strange, archaeologist from Earth who is brought to Rann by the Zeta Beam, ostensibly an attempt at communication (though Alan Moore suggests its creator had teleportation in mind all along).
Though Adam Strange had a good run in his early adventures and has been brought back for later series, all this traversing of Rannian geography has never been accompanied by a map. Jack C. Harris addressed that lack in The Amazing World of DC Comics #8 (1974):
Harris scoured Adam Strange's appearances to get all the details:
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