Cachoeira is a historic river town in Bahia, Brazil, situated on the banks of the Rio Paraguaçu roughly 500 kilometers from the river's headwaters in the Diamantina Upland.

The town marks the practical limit of navigation on the Rio Paraguaçu — vessels can travel upstream from the river's mouth at Todos os Santos Bay for only about 40 kilometers before reaching Cachoeira, where the river becomes unnavigable.

The Rio Paraguaçu itself is the largest river flowing entirely within Bahia state, draining a basin of nearly 55,000 square kilometers. Cachoeira sits across the river from the town of São Félix, the two communities facing each other on opposite banks.

The surrounding Paraguaçu valley has historically supported agriculture and cattle raising, and the river's upper reaches are known for deposits of black industrial diamonds.