The Glenmacnass Waterfall is a popular tourist destination and scenic viewpoint area in the Wicklow Mountains.

[2] The valley dates from the last glacial period called the quaternary glaciation or Ice Age, and contains moraines marking the positions of the ice-front as it retreated back towards the source area higher up in the centre of the Wicklow mountains.

[2][4] The GSI highlight an impressive moraine about halfway between the waterfall and Laragh and can be seen as a boulder-strewn mound running right across the valley.

[2] Further down the valley, on each side of the waterfall, dark grey-to-black, jagged schist rock (part of the Lower Palaeozoic Maulin Formation) can be seen jutting out; thus the waterfall has formed at the boundary between these two major rock types.

[2] The Glenmacnass Waterfall is a popular tourist destination and scenic viewpoint area in the Wicklow Mountains, and the entire Glenmacnass Valley can be accessed by the R115 road (also called the Military Road), which connects the Sally Gap to Laragh.