This article examines the commercial role of Ometepec, the largest human settlement in Eastern Costa Chica. Southern Mexico, and gateway to the Amuzgan realm The aim of the paper was to determine the linkages of regional commerce through a questionnaire-based research, looking at the origin of both products and buyers Ometepec´s hinterland comprises settlements in the coastal plain as well as in mountainous areas, the latter being one of the poorest regions in the state of Guerrero and, indeed in the whole country. The political boundary between Guerrero and Oaxaca heavily influences the perimeter of this commercial hinterland.