This study presents the geographical and nominal identification of the fishing areas of the artisanal fishery of the Patos Lagoon estuary (Brazil) as known by local fishermen. One hundred and twenty-four fishing areas were identified and georeferenced according to fishermen’s traditional ecological knowledge. The identification and mapping of the fishing areas as traditionally known and exploited by fishermen was based on participative mapping techniques (PRA, RRA). Nearly 80% of the designations of the fishing areas were known by fishermen only and are registered for the first time. Fishermen identify fishing areas according to depth, wooden logs used to anchor fixed nets, gradation of water transparency, and traditional use of certain areas. This study reveals the richness of knowledge held by fishermen, it illustrates their solid straight relationship with the natural environment where they live, and shows the potential uses of TEK for fisheries management. Fishermen identify fishing areas using four individual factors or a combination of them. These are: (a) areas with different depths that are grouped in three categories: those less than 1m deep are known as ‘‘croas’’, the places up to 5m deep are called ‘‘sacos’’, and places deeper than 5m are named as ‘‘canais’’ or ‘‘canaletes’’; (b) the existence of wooden logs vertically fixed in the bottom of the lagoon that are used to anchor fixed nets; (c) different gradation of water transparency; (d) the frequent (traditional) use of certain areas. The precise location of the fishing areas and their relationship with other data on fishing activity such as total catch, type of fishing gear used, type of boats, among others, can supply adequate yield models and scenarios that will predict catch strategies and help the maintenance of the fishing stocks. These data are also important when studying fish population dynamics, especially when assessing reproduction and nursery areas, which may eventually be the focus of protection.