The waterfall's geology tells a story that predates everything human in the valley. The water flows over Irish Ribband Group schists, metamorphic rocks that formed hundreds of millions of years ago, sitting within a metamorphic aureole of Leinster granite. During the last ice age, glaciers scoured the corrie at the head of Glensoulan valley, carving the steep backwall down which the River Dargle now plunges. The result is a natural amphitheatre of rock and water, framed by the slopes of Djouce mountain behind and ringed by the mixed woodland that the 7th Viscount Powerscourt planted when he established a deer park here in 1858.

That 1860 deer park was more consequential than the 7th Viscount could have imagined. In 1860, he introduced Japanese sika deer to the parkland around the waterfall, the first time the species had been brought to Ireland. The sika did not stay put. They spread across the Wicklow Mountains and eventually through much of eastern Ireland, interbreeding with native red deer and establishing populations that persist today. What began as a Victorian aristocrat's decorative impulse became one of the more significant introductions of a non-native species in Irish ecological history. The deer still roam the Glensoulan valley, visible among the trees on quieter days.

John Boorman chose Powerscourt Waterfall for the pivotal duel scene in his 1981 film Excalibur, where Arthur fights Lancelot beside the cascade. The location worked because it looked like no particular century, only raw landscape. Since then, filmmakers have returned repeatedly: Ron Howard shot scenes for Willow here in 1988, the television series Vikings used the waterfall and surrounding valley as a stand-in for Scandinavian landscapes from 2013 to 2020, and Cocaine Bear filmed here in 2023. The combination of dense woodland, exposed rock, and falling water creates a visual versatility that makes the location convincingly ancient, Nordic, or wild American depending on what the camera requires.

Powerscourt Waterfall is part of the Powerscourt Estate but accessed through a separate visitor entrance six miles from the main estate gate near Enniskerry. At the base, a picnic and barbecue area offers a surprisingly domesticated setting for a landscape that looks untouched. The waterfall can also be viewed from Ride Rock in Crone Woods on the slopes of Maulin mountain, where a 7-kilometre hill-walking circuit takes roughly three hours and offers elevated perspectives of the cascade and the full sweep of the Glensoulan valley. The approach from any direction involves narrow roads without shoulders, a reminder that this landscape was not designed for easy access and resists it still.