where does the river tay start and end
River Tay The River Tay (Scottish Gaelic: Tatha) 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 (Scottish Gaelic: Beinn Laoigh), 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.[1] Its catchment is approximately 2,000 square miles (5,200 km2), the Tweed's is 1,500 square miles (3,900 km2) and the Spey's is 1,097 square miles (2,840 km2).