Immediately after this, the river splits into two branches, the one that initially runs on the left side of the valley road is fed by another spring on the lower slope at about 445  m above sea level.

Opposite the Ittlinger mill, which follows shortly after and through whose grounds both branches then run, there is a large quarry in the White Jurassic limestone, which is mostly hidden by trees.

[2][4] The catchment area of the Ittlinger Bach is about 12.4 km² and extends more than 5.5 km from the rocky summit of the Hühnerstein (598m above sea level  ) southwest to the mouth.

[2][4] There are no open competitors in the upper catchment area, so that the drainage in the Karst flows underground in other directions than the surrounding dry valleys suggest, namely north-west and north of the catchment area in a northerly direction to the Trubach; east of it approximately southeast to the Regnitz, partly also south via the Sittenbach.

From the northern catchment area boundary, a long wedge of an Upper Cretaceous layer island extends far southwards almost to Ittlingen, at an altitude well below the White Jura ridges on the western and eastern borders.