From the area by the village of Balaton, by the Vajda well, the stream flows through the valley of Eger between the Bükk and Mátra mountains.

The Eger stream originates in the western foothills of the Bükk Mountains, in the Ózd-Egercsehi basin, at an altitude of 360 metres above sea level.

The stream runs southwards across the foothills of the western half of the mountain range in the north-south direction in the trench of its own fault line, then cuts through the Egri-Bükk valley to the Hevesi plain, which forms the northern edge of the lowlands, and then turns eastwards across the county border to form the western edge of the Borsodi-Mezőség region.

The stream finally flows into the artificially created Lake Tisza between Poroszló and Négyes at an altitude of 89 m above sea level.

When the reservoir was created, a large stretch of the former bed of the Eger stream and its surroundings was brought below the water level of the artificial lake.