It originates on the slopes of Ben Lui (Beinn Laoigh), around 25 mi (40 km) from the west coast town of Oban, in Argyll and Bute.

[2] In 2011, the Tay Western Catchments Partnership determined as its source (as based on its 'most dominant and longest' tributary) a small lochan on Allt Coire Laoigh south of the summit.

[2] A flow of 2,268 m3/s (80,100 cu ft/s) was recorded on 17 January 1993, when the river rose 6.48 m (21 ft 3 in) above its usual level at Perth, and caused extensive flooding in the city.

The highest flood recorded at Perth occurred in 1814, when the river rose 7 m (23 ft) above its usual level, partly caused by a blockage of ice under Smeaton's Bridge.

The largest rod-caught salmon in Britain, caught on the Tay by Georgina Ballantine in 1922, weighing 64 pounds (29 kilograms), retains the British record.

The river system has salmon fisheries on many of its tributaries including the Earn, Isla, Ericht, Tummel, Garry, Dochart, Lyon and Eden.

[13] In early December 2010, the first of the wild Tayside beavers was trapped by Scottish Natural Heritage on the River Ericht in Blairgowrie, Perthshire and was held in captivity in Edinburgh Zoo, dying within a few months.

[16] As part of the study into re-introduction, a trial release project was undertaken in Knapdale, Argyll,[17][18][19] alongside which the population of beavers along the Tay was monitored and assessed.

[16] Following the conclusion of the trial re-introduction, the Scottish Government announced in November 2016 that beavers could remain permanently, and would be given protected status as a native species within Scotland.

In the 19th century, the Tay Rail Bridge was built across the firth at Dundee as part of the East Coast Main Line, which linked Aberdeen in the north with Edinburgh and London to the south.

The event was commemorated in a poem, The Tay Bridge Disaster (1880), written by William McGonagall, a notoriously unskilled Scottish poet.

[22] The last vessels to operate the service were PS B. L. Nairn and two more modern ferries equipped with Voith Schneider Propellers, MVs Abercraig and Scotscraig.