The purpose of the present paper is to offer a systematic geographical and archaeological outline of the routes that linked the ancient Ganga Yamuna plain, beginning with Magadha or modern south Bihar, with the eastern and western sections of the Deccan plateau, respectively Andhra and Maharashtra. The fieldwork on which this study is based was done in 1999-2002 and rooted in our concern with the archaeological geography of the Ganga plain {cf. Chakrabarti 2001). All categories of geographical and archaeological information cited in this paper are based on our personal familiarity with the sites and areas concerned.