River Tay River Tay The River Tay () is the longest river in Scotland and the seventh-longest in the United Kingdom. The Tay originates in western Scotland on the slopes of Ben Lui (), then flows easterly across the Highlands, through Loch Dochart, Loch Iubhair and Loch Tay, then continues east through Strathtay (see Strath), in the centre of Scotland, then southeasterly through Perth, where it becomes tidal, to its mouth at the Firth of Tay, south of Dundee. It is the largest river in the UK by measured discharge. Its catchment is approximately , the Tweed's is and the Spey's is
Lough Tay Lough Tay Lough Tay (Irish: "Loch Té"), commonly called The Guinness Lake, is a small but scenic lake set on private property, in the Wicklow Mountains in County Wicklow, Ireland. It lies between the mountains of Djouce and Luggala, and is most easily viewed from above, from the R759 or the Wicklow Way as it descends past the J. B. Malone memorial. It is fed by the Cloghoge River, which then drains into Lough Dan to the south. It is not possible to visit Lough Tay without prior permission. The name is believed to derive from the Proto-Indo-European root *"teh₂w-",