Killarney National Park Oakwoods

Typically October 6–October 26

Two glacial lakes and the ruins of a sixth-century monastic settlement sit inside a valley of sessile oak, within Wicklow Mountains National Park. A 4.5km valley-floor loop passes the round tower and church walls under turning canopy, and the Spinc boardwalk climbs the ridge above the Upper Lake for a wider view of the color.

Don’t miss: Valley floor loop past monastic ruins, 4.5km · Sessile oak woodland around both lakes · Spinc boardwalk above the Upper Lake

Typically October 6–October 26

A 4km nature trail follows the shore of Lough Veagh through sessile oak, birch and hazel woodland below the quartzite peaks of the Derryveagh Mountains, among the largest stretch of native woodland left in Donegal. At Glenveagh Castle the walled garden, planted with exotics since the 1870s, turns red and gold alongside it, while red deer rut in the glen through October.

Don’t miss: 4km native oak, birch and hazel trail · Walled garden at Glenveagh Castle · Red deer rut in the glen

Samuel Hayes began planting this arboretum above the River Avonmore in 1777, and the 500-acre estate now holds sequoia, Douglas fir, larch and oak gathered from around the world, some among the tallest trees recorded in Ireland. A 1,440-metre treetop boardwalk threads the canopy near the birthplace of Charles Stewart Parnell.

Don’t miss: Arboretum planted from 1777, 8,000+ trees · Sequoia and Douglas fir groves · 1,440m treetop boardwalk