Reichenau an der Rax is a market town in the Austrian state of Lower Austria. It lies at the foot of the Rax mountain range, on the Schwarza river, which is a headstream of the Leitha.
The town's position at the base of the Rax places it within the mountainous terrain of eastern Lower Austria, where the Schwarza flows through the valley before continuing toward the Leitha river system. Its setting on the river and beneath the Rax range defines its basic geography.
As a market town, Reichenau an der Rax holds that administrative status within Lower Austria. The settlement is located in the eastern part of the country, near the border with Styria, in a region shaped by the rivers and mountains of the area.