An Bun Beag (anglicised as Bunbeg), meaning "the small river mouth", is a small Gaeltacht village and townland in County Donegal, Ireland. It is officially the smallest townland in Gaoth Dobhair (Gweedore), but today the name Bunbeg is used to describe a large region of the parish. It is situated between Derrybeg and Dore and is home to many of Gweedore's amenities and businesses and local headers.
On the afternoon of Tuesday, 23 June 2009, a severe thunderstorm struck Gweedore and neighbouring areas. It was centered on the adjoining villages of Bunbeg and Derrybeg and lasted for several hours causing two rivers to burst their banks, flooding houses, shops and factories, ripping up roads and destroying bridges. Lightning which lasted for two hours damaged power lines and caused a major breakdown of mobile phone signals, causing people trapped by the floods to be unable to communicate. Up to 20 houses were cut off from the outside world after three access bridges were carried away by the swollen rivers. 
Described as the worst storm 'in living memory', it was also the most severe since 1880 when 5 people drowned in Derrybeg. Owing to the highly localised nature of the storm the areas of maximum rainfall missed the network of rain gauges but the Irish Meteorological Service estimate that between 2pm and 6pm up to 60 mm (2.4 in) of rain fell at the core.
- Placenames (Ceantair Ghaeltachta) Order 2004
- "Tory island ferry". Archived from the original on 2015-02-10. Retrieved 2015-07-30.
- "Horror storms flood west Donegal"
- Donegal Democrat, Clean up underway after freak flash flood in Gweedore, 24 June 2009 Archived 17 February 2013 at Archive.today
- Met Service report on the flood
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