The Derna is a right

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainag ...

of the river Valea Fânețelor in

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, a ...

. It flows into the Valea Fânețelor in Sărsig.Derna (jud. Bihor)
e-calauza.ro Its length is .

References

Rivers of Romania Rivers of Bihor County {{Bihor-river-stub