In Gaelic, Baile a' Chaolais means the village by the narrows, and the narrows in question are Caolas Mhic Phadraig, Peter or Patrick's son's narrows, at the mouth of Loch Leven. Until 1927 no road reached the head of the loch, so getting east-west across this country meant the Ballachulish Ferry, established in 1733 and operating for the next 242 years. It closed in December 1975, the day the Ballachulish Bridge finally opened. The village stretches along the south shore in a thin line. Beinn a' Bheithir, the mountain of the thunderbolt, rises behind it, holding two Munros: Sgorr Dhearg, the red peak, and Sgorr Dhonuill, Donald's peak. The fields of Gleann a' Chaolais have been turned into a nine-hole golf course called Dragon's Tooth, in honour of the local legend that Beinn a' Bheithir was the lair of a serpent.

Ballachulish slate is good slate. It split cleanly, weathered well, and lasted on a roof for the better part of a century. The two great Scottish cities, Edinburgh and Glasgow, used it on their tenements and townhouses through the entire Victorian era. The quarrymen who cut it lived hard. Between 1902 and 1905, two prolonged industrial disputes paralysed the village. The first began in July 1902 over the summary dismissal of Dr Lachlan Grant, the quarry's medical officer, and grew into a twelve-month lockout that lasted eighteen months in total. The workers also objected to unsatisfactory contracts, inadequate wages, and the inflated prices the company charged for powder, coal, and the other materials they were required to buy. A second dispute broke out in 1905 against the quarry manager. A new company was formed in December 1907 and quarrying continued until 1955. When the pits finally closed, the village was abruptly impoverished, and the slate mountains the quarries had piled up around the houses were left for the unemployed to face every morning.

Overlooking the narrows is a monument to James Stewart of Acharn, known as James of the Glen, hanged on the spot for a crime of which he was not guilty. The crime was the assassination of Colin Roy Campbell of Glenure, the Red Fox, government factor on the forfeited Stewart estates, shot from cover near Ballachulish in 1752. James Stewart was tried at Inveraray before a jury of Campbells and convicted on circumstantial evidence. He went to the gallows insisting he was innocent. Robert Louis Stevenson built his novel Kidnapped around the case, and the question of who actually pulled the trigger has stayed open for more than two and a half centuries. In 2001, an eighty-nine-year-old descendant of the Stewarts of Appin named Amanda Penman alleged that the killing had been planned in retaliation for the Red Fox's role in the local Highland Clearances by four young Stewart tacksmen, without James Stewart's knowledge, and carried out by their best marksman, Donald Stewart of Ballachulish. The monument still says hanged on this spot for a crime of which he was not guilty. The village has not forgotten.

In 1903 the Callander and Oban Railway opened a branch to Ballachulish. The line closed in 1966, the year the village's slate mountains and the post-war Highland economy were both running down. The old terminus at Laroch is now the doctor's surgery. The station at Kentallen, five miles south, included a pier and afterwards became the Holly Tree Hotel. The old railway line is now National Cycle Route 78, returning the view to a slower kind of traveller. South Ballachulish also has Ballachulish House, a country house that for years served as a hotel and was reputed to be haunted, its drive ridden, in local belief, by a headless horseman. The graveyard of the former St John's Episcopal Church holds an exceptional collection of nineteenth-century gravestones, each carved from the village slate. Even the dead here are roofed by what came out of the quarry.