Geographically, the "Sertão" consists mainly of low uplands that form part of the Brazilian Highlands. Most parts of the sertão are between 200 and 500 meters above sea level, with higher elevations found on the eastern edge in the Planalto da Borborema, where it merges into a sub-humid region known as agreste, in the Serra da Ibiapaba in western Ceará and in the Serro do Periquito of central Pernambuco. In the north, the "Sertão" extends to the northern coastal plains of Rio Grande do Norte state, whilst in the south it fades out in the northern fringe of Minas Gerais.