But it isn't just the number of visitors flocking to the 22-mile stretch of water north-west of Glasgow that is causing problems: it is the speed at which they travel when they get there.
When Queen Victoria visited in 1869, she came by one of the paddle-steamers that had been taking passengers up the River Leven from the Clyde for more than 50 years.
These days the cruisers use speedboats and jet skis that rush across the water at more than 60 miles an hour. Last weekend a woman died after two of them collided.
The Department of Transport's marine safety inspectorate is to hold its own investigation, separate from the police and fatal accident inquiries (the Scottish equivalent of an inquest). There is talk of speed limits. But after decades of disharmony between the overlapping local authorities that govern the loch, no one expects an easy solution.
Tommy Daniels, a Loch Lomond boatman since 1939, has been writing letters to the various authorities for years to try to draw attention to the problems. Mr Daniels's old-fashioned wooden boat does seven to eight knots - just under 10mph. 'The plastic boats can fly up and down here at 60mph,' he says. 'Drivers don't know one end of the loch from the other; most don't even know where the engine of their boat is.'
Most of all he is worried about drink. 'You can't drink and drive on the lochside road, but out here you can do anything you like. I don't come here at the weekend anymore. They are destroying it.'
Queen Victoria wrote in her diary of her cruise on Loch Lomond: 'Nothing could be finer or more truly Alpine, reminding me much of the Lake of Lucerne; only Loch Lomond is longer.'
Her comments assured the loch instant fashionable status. But the tourist boom actually started about 200 years ago, when the geographer T Richardson published his Guide to Loch Lomond in 1799. Its fame was 'sounded by every traveller who had seen it', Richardson wrote. 'No place of its kind in Europe is more resorted to, foreigners of every description visit, returning amply satisfied with their romantic beauties; beauties which at once please the eye and gratify the fancy.'
That brought the famous flocking to the place. But a song helped too. 'The Bonnie Banks O' Loch Lomond' derives from the failure of the 1745 Jacobite rising. Two men from the Lomond clan, Colquhoun, were sentenced to death. One was let off to return home and tell the story. The dead one's sweetheart says that she will meet her loved one again in heaven - a reference to her intended suicide.
The 'high road' and 'low road' in the chorus refer to the Scottish belief that if a clansman died, his spirit was transported back to his birthplace by the 'faeries', who always travelled underground.
Jacobite history, folklore, and a suicide were thus reworked from older songs in 1836 by Lady John Scott of Buccleuch - the Joni Mitchell of her day - who died, aged 90 in 1900.
But the 'Bonnie Bonnie Banks' have paid for their fame. Ian Thompson has worked on the loch at Luss village for 37 years. Last week he watched three men being rescued when their speedboat hit rocks. 'If there is an easy answer, I don't know anyone who knows what it is,' he said.
At Loch Lomond Marina, in Balloch, at the south end of the loch, director Simon Kitchen blamed 'a few irresponsible idiots giving anybody who uses speedboats or jet skis a bad name'.
A multimillion pound industry would be killed off if new speed regulations were introduced, Mr Kitchen said. 'At the moment we have one park warden for the whole area. And this isn't a park anyway. He's frustrated. We're frustrated. I wish someone had answers. We don't'