Marble Arch Caves Global Geopark, Geological site across Northern Ireland and Republic of Ireland.

Marble Arch Caves Global Geopark is a cave system spanning Northern Ireland and the Republic of Ireland, featuring limestone formations with underground streams, stalactites, stalagmites, and natural chambers. The landscape displays karst topography with multiple entrances and interconnected passage networks.

The geopark was designated in 2001, one of Europe's first, and is jointly run by Fermanagh and Omagh District Council and Cavan County Council. Its caves are developed in the Asbian Glencar Limestone and the Knockmore Limestone Member of the Dartry Limestone. Their age is unknown, but parts date back over 380,000 years. The area records 7,000–8,000 years of human occupation since the last ice age.

Local communities have valued these caves for thousands of years, as shown by ancient tools and bones found throughout the site. Visitors can observe how the natural chambers and surrounding landscape shaped the lives of earlier inhabitants.

Visitors are advised to wear sturdy footwear and warm clothing, as underground temperatures stay cool throughout the year. The best time to visit is between spring and autumn, when tours run regularly.

The geopark was among Europe's first, designated in 2001, and is jointly run by Fermanagh and Omagh District Council and Cavan County Council. Its sites are scattered like an archipelago across the border, with concentrations around Lower Lough Erne and south of Belcoo. The caves themselves are of unknown age but partly date back over 380,000 years.