The Gearagh, Nature reserve and wetland near Macroom, Ireland.

The Gearagh is a nature reserve consisting of small islands separated by narrow water channels, lined with oak, ash, hazel, and hawthorn trees across roughly 300 hectares. The reserve forms a complex wooded wetland system shaped by the river and seasonal flooding patterns.

The site was significantly transformed in 1954 when flooding for hydroelectric dams required relocating residents and removing centuries-old trees. This major intervention led eventually to its protection as a nature reserve.

The Irish name An Gaorthadh means "wooded river-valley" or "river-bed"; Seamus O'Donoghue also records An Gaoire. Local folklore links the maze of channels to the Meascan Maraiocht, mischievous spirits said to confuse and lead visitors astray. Before the 1954 flooding the secluded terrain sheltered poitín makers, and the area was known for a potent, high-quality brand.

Access is from a marked detour off the N72 Macroom–Killarney road at Templemartin crossroads, leading to a car park in Kilmichael parish; paths from there cross the islands and waterways, and boats can be hired at the car park to go upriver. Water levels in the reservoir change, so check conditions before setting out and wear footwear for wet, muddy ground.

The Gearagh is the only surviving alluvial woodland in Western Europe, and before the 1954 flooding it was the last pure stand of ancient riverine forest intact since the last ice age. Environmental biologist Kevin Corcoran called it one of just four such systems on the whole planet. Its maze of channels and soft mud banks once kept local Gardaí out, making it a haven for poitín makers.