Goofs

When Rob Roy jumps off the bridge, his hands are tied together, when he hits the water and jumps back up, they are untied, and when he comes back up again they are tied back together

When Killearn takes from MacDonald the paper about the "new world," he crumples it into a ball. But when he later hands it to MacGregor, it's smooth and has clearly never been crumpled.

In the final sword fight, Archie's blade is bent and straight in different shots.

When Mary goes to the edge of the water, just before the soldiers arrive, she ties her shawl into a knot around her shoulders. When she runs back to the house, her shawl is loose.

When Archie is chasing MacDonald through the woods on horseback, MacDonald's hair is tied back in some shots.

As MacGregor and the Marquis of Montrose meet in the latter's gardens to discuss their business, the entrance is shown prominently adorned with the coat of arms of John Drummond, Earl of Perth instead of Montrose's own red roses. This scene was shot at Drummond Castle, which (ironically) belonged to political rivals of the real Marquis.

Throughout the film, which takes place in 1713, James Graham is referred to and addressed as the [4th] Marquess of Montrose. In reality, James Graham was elevated to become the [1st] Duke of Montrose in 1707. It follows that the scene where the Duke of Argyll "pulls rank" on him is incorrect, as the two would have been of equal standing at this point in time.

The Duke of Argyll is depicted as a man in his sixties. At the time this film is set John Campbell, 2nd Duke of Argyll was in his early thirties.

The historical Robert Roy MacGregor was nine years older than James Graham (Montrose) and eleven years older than John Campbell (Argyll). Liam Neeson was younger than the actors portraying them by twelve years and twenty-six years, respectively.

A stunt double is visible when Rob Roy is riding the horse he steals from the soldier who killed Alasdair. Though seen from the distance is easy to notice that is not Liam Neeson who's riding the horse.

At the 63 min mark, Archibald is seen bouncing so badly on the back of his horse it's laughable.

Several of the horses seen at the 1 hour 44 min mark are swayback.

When Rob and his men are seen returning the cattle, one of the cows accidentally hooks its right horn under Liam Neeson's left arm for a second or two. He pulls away quickly and slaps the cow on the rump, but he is fortunate that he was not injured. This seems to have been an accidental incident, unplanned, which made it into the final cut of the film.

It was, and sometimes still is, traditional for Scotsmen to not wear underwear while wearing kilts. Neeson's Rob Roy apparently favored "tighty-whities" as seen when he's being dragged behind a horse.

The redcoats under Cunningham's command have socket bayonets. Correct bayonets for the period are plug types.

The redcoat infantry under Cunningham's command wear grenadier mitre caps with the white horse emblem of the House of Hanover - not used by any unit in England or Scotland until the reign of George I.

The Gaelic song "Aileen Duin", sung at the fireside gathering when Rob Roy and his "clan" are celebrating the business deal with Montrose, was composed after 1788. Rob Roy died in 1734.

When Killearn leads McDonald into the pub, an overhead fluorescent lamp can be seen.

When MacDonald is thrown from his horse by a rope across the path, you can see the harness and line that pulls him backwards just before he gets to the rope.

When Robert Roy MacGregor hides in the corpse of a highland cow, Montrose's man leading the chase says, "What a stench! Let's get downwind." To get away from an odor, a person needs to place himself upwind, not downwind.