Scotland's Loch Ness gets all the publicity, but serious lake monster researchers know that there is a Northern Latitude "belt" that seems to have the majority of Lake Monster sightings. Other Scottish lochs have recorded sightings, as do lakes in Scandinavia, Russia, China, the United States, and Canada.
Ireland is no exception. Here is footage shot in 2009 by a researcher of an Irish lake that supposedly is home to such a beastie. (I'm linking because my uploads seem to be having problems.)