O'Sullivan's Cascade is a striking waterfall tucked within Tomies Wood in Killarney National Park, nestled between the shore of Lough Leane and the slopes of Tomies Mountain.

Fed by mountain runoff, the cascade tumbles through ancient oak woodland before reaching the lake edge, and can be accessed either on foot or by boat.

A round trip from the Tomies Wood car park to the cascade is roughly 3 km, taking between 45 minutes and two hours depending on pace.

A flight of steps — recently rebuilt with shallower, more even treads — leads down to the water's edge, where the falls offer panoramic views across Lough Leane toward Killarney town.

The site carries a well-known piece of Irish folklore: legend holds that whiskey, not water, once flowed from the cascade, and that Fionn Mac Cumhaill and his warriors, the Fianna, used the surrounding mountain as their summer hunting ground.

The spot is also popular as a wild swimming destination in warmer months.