This study describes the geomorphological patterns in the estuary of the Assu river, state of Rio Grande do Norte, northeastern of Brazil. The 20 m contours of the topographic maps (Macau and Porto do Mangue), at the 1:50,000 scale, were manually digitized and analyzed using SPRING 5.2. Afterwards, the techniques used in this study consisted of the preparation and analysis of hypsometric, slope, hillshade maps,...