A basin in itself is a fundamental study unit to recognise morphogenetic processes. Geomorphologic analysis was used to provide information about the basin characteristics, and to understand the landscape evolution. Sao Miguel River is one of the principal tributaries of middle Jequitinhonha Valley. This basin is located between 16°25' and 16°52' southern latitude and 40°45' and 41°16' western longitude. The basin has 2,200 km² surface, which contains in itself two different component landscapes, strongly related to the geological structures. The first component, at the eastern part of the basin, belongs to the Jequitinhonha Depression, which presents a well defined stream-channel network along a range of flatted forms. The channel-network on this first component has a medium drainage density and a marked dendritic drainage pattern, E-W direction. The altitudes in this area range from 600m to 900m. It is caracterised by flat hills, flat valleys and numerous occurrences of granite domes, formed under conditions of strong chemical weathering. The western part of the basin, corresponding to the second component, belongs to the geomorphologic unit of Jequitinhonha Plateau. It shows flat surfaces known as "chapadas" with average high of 500 m and maximum altitudes of 900m. This is an area highly dissected, with a high density channel-network, dendritic drainage pattern and SE-NW direction. The component's valleys are entrenched, and slopes quite steep. There exists large accumulations of corestones at the Sao Miguel's river course, as well as on lower slopes around the massive domes, probably, settled there by gravity.