Qualla: Pouldergaderry Sinkhole

Pouldergaderry Sinkhole: Introduction

Sat, 23 May 2026 00:00:00 GMT

Photo credit Scott Ehardt, Public domain. The first surveyors who mapped this corner of County Kerry in 1829 drew a circle on their Ordnance Survey sheet near Milltown and marked it as something other than ground. Pouldergaderry was already old then - a great pit in the limestone bedrock, roughly 80 metres across and 30 metres deep, with mature trees growing out of its floor like a garden someone had dropped into the earth. Two centuries later, the trees are still there. The hole hasn't moved. Sinkholes mostly don't - except when they do, and the ones that do are why the rest are interesting at all.

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Image: Scott Ehardt | Public domain

Pouldergaderry Sinkhole: What's Under the Field

Sat, 23 May 2026 00:00:00 GMT

Photo credit Public domain. Pouldergaderry sits in the townland of Kilderry South, in a swath of County Kerry where limestone lies close to the surface. This is karst country - the same kind of geology that pocks Slovenia and Croatia and the Yucatán Peninsula with depressions, caves, and disappearing rivers...

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Image: Public domain

Pouldergaderry Sinkhole: How a Hole Becomes a Forest

Sat, 23 May 2026 00:00:00 GMT

Photo credit Public domain. Mature trees inside a sinkhole are odd things. They suggest stability - if the pit were actively collapsing, mature trees couldn't get a foothold. Geologists divide sinkholes into types based on how they form: solution sinkholes, where soil settles slowly into widening cracks in ...

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Image: Public domain

Pouldergaderry Sinkhole: Family Resemblances

Sat, 23 May 2026 00:00:00 GMT

Photo credit U.S. Geological Survey (USGS), Public domain. Every karst landscape has its own version of Pouldergaderry, and a few are spectacular. The Xiaozhai Tiankeng in China's Chongqing province plunges 662 metres - a sky hole, in Chinese, with vertical walls and a river at the bottom. The Cave of Swallows in Mexico is 372 metres dee...

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Image: U.S. Geological Survey (USGS) | Public domain

Pouldergaderry Sinkhole: The Other Kerry Karst

Sat, 23 May 2026 00:00:00 GMT

Photo credit Peter1936F, CC BY-SA 4.0. Sinkholes in Ireland tend to be quieter than the headline-grabbing collapses in Guatemala City or Florida. The bedrock here is older, the water table relatively stable, and most of the dissolution happened a long time ago. But the karst is real. The Burren, north of County Kerry ...

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Image: Peter1936F | CC BY-SA 4.0

Pouldergaderry Sinkhole: Reading the Ground

Sat, 23 May 2026 00:00:00 GMT

Photo credit Ajay Suresh from New York, NY, USA, CC BY 2.0. Most people walk past karst features without recognising them. A dry valley with no stream. A spring that appears partway down a hill from nowhere obvious. A pond that never freezes. A field with a dimple in it. Pouldergaderry is unsubtle - the dimple is 30 metres deep - but the ...

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Image: Ajay Suresh from New York, NY, USA | CC BY 2.0