It flows for 66 kilometres and has a basin area of 542 km².

It begins near Gervėnai village and crosses the Lake Obelija at upper course.

The most important settlements along the Peršekė are Krokialaukis and Balbieriškis.

Peršėkė joins the river Neman from its left side.

This article related to a river in Lithuania is a stub.