It is a tributary of the Tietê River, which it joins in the reservoir created by Barra Bonita Dam.

There is also another Piracicaba river in the state of Minas Gerais, named after the one from São Paulo state, since the early colonizers of Minas Gerais largely came from São Paulo.

The basin of the Piracicaba River extends over an area of 12,531 km², located in the southeast of the state of São Paulo and extreme south of Minas Gerais.

After crossing the city of Piracicaba, it receives the waters of its main tributary, Corumbataí river.

[2] The watershed of the Piracicaba River is located in one of the most developed regions of the state of São Paulo, encompassing municipalities such as Bragança Paulista, Campinas, Limeira, Americana, Atibaia, Rio Claro, Santa Bárbara d'Oeste and Piracicaba.