The sources of the Rehlingbach (Hraniční potok) lie on the south side of the 763 meter high glass mountain (Sklářský vrch) in the nature reserve Farské bažiny (parish swamp) in the Czech Republic.[5][6] From there it makes its way south. In doing so, he takes in streams coming from the right and left, which rise on the slopes of the mountains to the east and west.
On the east bank of the Rehlingbach are from north to south the Hufnagelberg (Pustý vrch, 745 m), the Kollmer Berg (Chloumek, 730 m), the Liščí vrch (710 m), the Ahornsberg (Javorný vrch, 680 m), the Hammer slope (Hamerský vrch, 605 m).
On the west bank of the Rehlingbach stream, from north to south, are the toll hill (Mýtný vrch, 753 m), Myslivecký vrch (687 m), the former village of Kollerhütten (Kolerova Huť), the river hill (Flusárenský vrch, 687 m), the Vysoký les (690 m).[7]
The Rehlingbach continues to flow through the former towns of Neuhütte (Nová Huť) and Fuchsloch (Liščí Díra), through the upper and lower border ponds (Horní and Dolní Hraniční rybník), through the former village of Reichenthal (Hraničky), to the German-Czech border he reached the former Ernestinen Hammer (Arnoštin Hamr). Here the Myší potok (Mausbach), which has its source in the Mausbrunnen about one kilometer to the west and is still on German territory, flows from the right into the Rehlingbach.
From now on, the Rehlingbach flows further south along the border line.[8] It passes the towns of Stöckl and Reichenau further to the west. The Forellenbach flows from the right between Reichenau and Grafenau. It then flows east past Grafenau, Speckermühle, Brunnenhof, the battlefield of 1621 and Oberströbl.
South of Oberströbl it crosses under the A6 motorway. It flows around the Kagererholz in an arc to the east. To the south, the Rotlohbach flows from the right. Then the Rehlingbach separates from the boundary line and flows into the Katharinabach at Pfrentschweiher, which forms the upper reaches of the Pfreimd. When the Rehlingbach flows into the Katharinabach, it changes its name to Pfreimd.[9]
16.2 kilometers of the 22.57 kilometer long creek are on Czech territory.[10]