Posejnele [pɔsɛi̯ˈnɛlɛ], is a village in the administrative district of Gmina Giby, within Sejny County, Podlaskie Voivodeship, in north-eastern Poland, close to the borders with Belarus and Lithuania.

The village is located in a picturesque area, on the edge of the Augustów Primeval Forest.

There are several nature reserves nearby, including beaver dams and runs for Lek mating.

Not far from Posejnela, there is a hill overgrown with forest, called grodzisko (hillfort).

Access to it was most probably in the south-western part, where remains of a palisade structure (possibly a watchtower) can be found.