Röhrenbach is a town in the district of Horn, in the Austrian state of Lower Austria. It lies in the Waldviertel, the northwestern quadrant of Lower Austria, a region bordering the Czech Republic and characterised by granite plateaus, forests and farmland rather than the alpine terrain associated with western Austria.
The municipality is administratively part of the Horn district, one of the smaller districts of Lower Austria, whose seat is the town of Horn. Like most settlements in this part of the country, Röhrenbach is a rural community; the surrounding landscape is given over chiefly to agriculture and woodland, and the area is served by the road network linking the district's towns and villages.
Röhrenbach is situated in the same general part of Lower Austria as the historic Waldviertel towns of Horn and Zwettl, and it shares the region's continental climate, with cold winters and relatively dry summers compared with the Austrian Alps to the south and west. The town is not among Austria's major tourist destinations and functions primarily as a residential and agricultural community within its district.