The Merzalbe rises in the middle of the Palatine Forest, west of the Palatine Watershed and between the two hills of the Weißenberg and the Eschkopf at a height of just under 500 metres. Its source is enclosed by the Christelbrunnen well. As it heads in a southwesterly direction the Merzalbe flows through the valley below the village of Leimen and then through Merzalben. After it empties from the right into the Rodalb near the Riegelbrunnerhof, a hamlet belonging to Münchweiler. Its waters then flow down the Schwarzbach, Blies, Saar and Moselle before finally reaching the Rhine.