Holtsås is a settlement in Midt-Telemark Municipality, in Telemark, Norway. Holtsås lies in the Scandinavian mountains. The nearest city is Kongsberg, 30 km to the northeast. Among the landmarks around are Heddal Stave Church (16.7 km), Old Bø Church (16.7 km) and Sauherad Church (4.9 km). Among the natural features are Nybufjellet (8.8 km) and Skrim (15.7 km).