At its south-eastern angle, the loch receives the waters of the Endrick, from a lovely valley celebrated in the song "Sweet Ennerdale", or "The Gallant Grahams". The river separates Dunbartonshire from Stirlingshire, and its mouth, formerly farther to the west, gave the name of Aber to the district already mentioned. The wild and secluded region about its present mouth is notable for its variety of bird - life, among the richest in the country,

Several great families have had their seat on these river banks, Drymen was the original home of the Drummonds, descended, it is said, from a Hungarian who came into the country in the train of the Saxon princess Margaret, the destined queen of Malcolm Canmore. They took their name from the place Druman, the plural of drum, a rising ground. Later, in 1282, the first of the Chiefs of the Buchanan Clan obtained from the Earl of Lennox a charter of the lands on the eastern side of the loch from the Endrick northward, along with the island of Clairinch, the name of which became the Buchanan slogan or battle-cry. Of that clan, the most notable scion was the famous Latinist, George Buchanan. Another was Buchanan of Auchmar, an estate on the slope of the Conic Hill which ends at Balmaha, whose history of his own and other clans is one of the most authentic records of the Highlands. In 1682, the Buchanan lands were purchased by the grandson of the Great Marquess of Montrose, whose son was created a duke in 1707.

The Dukes of Montrose had their seat at the plain old Buchanan House by the Endrick here, till it was burned about 1870 and the present Buchanan Castle was built. One of these dukes, in the early years of the nineteenth century, was bringing home his bride. As they crossed Drymen Bridge, he pointed out her future home, and, much to his surprise, as she looked she burst into tears. In great concern he inquired the cause. It was so bare a place, she said, and such a contrast to the lovely wooded country from which she had come. Next day, the Duke sent for the greatest landscape gardener of the time, "Capability" Brown, and gave him carte blanche to lay out policies and plant the valley with trees. As a result, the valley about the Endrick mouth to-day is one of the most beautiful sylvan demesnes in Scotland. A special feature are certain woods on the high, sloping country above the castle. These appear from the distance in the form of the three great schiltrums, or circular bodies of troops which comprised the Scottish army under Sir William Wallace at the Battle of Falkirk in 1298, when Sir John the Graham, the heroic ancestor of the Dukes of Montrose, was slain.

Besides Buchanan House, the chiefs of the name had a stronghold on Stracashel Point, farther up the loch. The parish, however, was originally known, not as Buchanan, but as Inch Cailleach, the ancient kirk and burying-ground being situated on the beautiful island of that name, off Balmaha. Originally the island itself took its name, the Isle of Women, from the religious house founded there by Kentigerna, the mother of St. Fillan, and till a recent period it was the most sacred burying-place of the clansmen of the loch shores. As already mentioned, the tombstone is still to be seen there which covers an ancestor of Rob Roy.

The present roadway at Balmaha is not the pass through which the famous cateran was wont to drive his stolen cattle. This is to be seen cleaving the mountain barrier higher and farther eastward. In Rob Roy's time this was regarded as one of the main gateways of the Highlands, and during the Jacobite rising of 1715 the Duke of Argyll kept a garrison at Drymen to control it, Even when his herds were safely through the pass, Macgregor had a good many miles to go through the country of the Duke of Montrose before he reached his own patrimony of Craigroyston, along the rocky foot of Ben Lomond and about Inversnaid. As he had absconded with various sums of money lent by the Duke of Montrose, the latter caused his property at Inversnaid to be legally attached, and, resenting the rigour with which his wife and family had been treated by the military on that occasion, when his house of Craigroyston was burned, Rob took to a sort of war on his former patron. Notably he seized the Duke's factor, who was no less a personage than Graham of Killearn, Sheriff-Substitute of Dunbartonshire, along with certain rents he had just collected, and his books and papers. The captive was confined first in a cave, known as Rob Roy's Prison, still to be seen in the rocks of Craigroyston between Rowardennan and Inversnaid, and then on an island in Loch Katrine. After about a week, as the Duke would pay no ransom, Graham was allowed to go, with his books and bills, but without his cash. To stop such lawlessness, at the Duke's suggestion, in 1713 a fort was built at Inversnaid, regarding which a tradition exists that Captain James Wolfe, afterwards the conqueror of Quebec, once was the commander. But Macgregor evaded all attempts at capture, and died at last in his bed at Inverlocharig in Balquhidder about the year 1740.

Loch Lomond from Inversnaid

Rob's three sons, James, Duncan, and Robin Oig, for a time carried on their father's business of cateran, but their career was brought to an end by an act which could not be tolerated, Robin Oig's wife, a daughter of Graham of Drunkie, having died, the brothers plotted to make their fortunes by securing an heiress for him. On a December night in 1750, they beset the house of Edinbelly near Balfron, overpowered the male inmates, and carried off a rich young widow, Jean Kay or Wright. Bringing her to Rowardennan, they put her through a form of irregular marriage with Robin Oig. Their father had carried off his wife, Helen, in a similar fashion, and no doubt the brothers thought they had done a fine thing; but the Government decided that the achievement was now an anachronism. The three Macgregors were captured; James escaped from Edinburgh Castle, Duncan was dismissed, and Robin Oig was hanged. Strangely enough, Jean Kay herself to the last refused to prosecute.

It is worth noting how, more vivid than the actual historic events — the burning of Macgregor's house of Craigroyston, or the capture of his son Robin Oig at Inversnaid — seems to-day the scene described by Sir Walter Scott, of Rob Roy bidding farewell here to his kinsman, the pawky and cautious, but kind and stouthearted Bailie Nicol Jarvie. Some seventy years later, occurred the visit of Wordsworth, his sister Dorothy, and the visionary Coleridge. They got their clothes dried after a wet day, then parted company, Coleridge to go home "in a kind of huff"; while Wordsworth was to immortalize the Highland girl whom he saw reaping and singing amid the lovely surroundings of "the lake, the bay, the waterfall". Sixty years later, Alexander Smith, the Glasgow poet, reached Inversnaid, wet and weary after a three days' tramp, and at night by the chimney nook in the inn wrote his sonnet on "Wordsworth's Inversneyd". But still it is the figure of "the bold Rob Roy" which dominates the scene.