Cascata do Poço Negro is small but scenic waterfall near Sernadinha (Manhouce) in the region Viseu, Portugal.
In Sernadinha there is a small sign for Poço Negro. A small road leads to the waterfall. There are several pockets in the road where you can park your car. From the road it is a short walk to the scenic Cascata do Poço Negro.
I am not sure when the best time is to visit Cascata do Poço Negro. A few hundred meter upstream there is a dam. So it seems the waterfall is regulated.
Poço Negro means black well is a perfect spot for a swim.