Sam's line at the end of the film ("Well, I'm back") is also the last line of the "King" novel.

When Gandalf is talking about the gathering of the armies of Sauron, the next shot shows the Corsairs on a ship. Walking there from right to left is Peter Jackson in a cameo as a Corsair pirate. In the Extended DVD, at the start of Disc 2, he is actually pierced in the chest by Legolas' arrow and dramatically dies!

The New Zealand army was used as extras for Aragorn's Rohirrim/Gondorian army. Though its presence was appreciatively efficient, its fighting was overly enthusiastic, and did not tend to pretend fight. Quite a few injuries were incurred as a result of the army's fierce fighting with the stunt doubles and WETA weapons were often destroyed in the melee.

Author J.R.R. Tolkien wanted this book to be titled "the War of the Ring." He felt that "The Return of the King" gave away the ending.

At the end of the film, young Elanor Gamgee is played by none other than Sean Astin's own daughter in a cameo. Not only that, but Frodo Gamgee (the baby) is played by Maisie McLeod-Riera, the daughter of Sarah McLeod, who plays Sam's wife, Rosie.

In later years (according to the book), after he is about 100 years old, Sam also sails into the West to be with Frodo. There is a reference to this in the line from Annie Lennox's song 'Into the West': 'Don't say, we have come now to the end, white shores are calling - you and I will meet again.' Sam is allowed to sail because he also bore the burden of the One Ring to the Tower at Cirith Ungol, on their way to Mt. Doom.

In the scene of Sam and Frodo on the slopes of Mount Doom, the entire scene has been flipped. Peter Jackson wanted the Hobbits to travel from left to right across the screen for all three movies, so the editors had to flip this scene to achieve that. This is also why any cuts/dirt smudges on their faces seem to change sides. Only when Frodo and Sam return to the Shire and go to the Grey Havens, do we see them traveling right to left.

Towards the end of the film, when Aragorn was crowned and Arwen appears, there was a brief shot of Eowyn and Faramir looking at each other and smiling. This is a reference to the book. In the book, Eowyn and Faramir fell in love when they met in Gondor.

Billy Boyd (Pippin) isn't the only composer in the movie; Viggo Mortensen wrote the melody for the song he sings at Aragorn's coronation (the lyrics are from the book).

Bruce Spence's mouth is enhanced with a cut laden prosthetic as the Mouth of Sauron, to represent the evil he has spoken for Sauron. During editing, the CG specialists toyed with the idea of having the mouth lie vertically on his face. Though the mouth chosen is horizontal, it's digitally enlarged by about 50% for this scene to fill the only opening within the helmet, creating the very disturbing unsettling image. (Extended Edition).

(Extended Edition)The song sung in the Houses of Healing scene is sung by Liv Tyler.

The quarry that Minas Tirith was built in was also the location that Helm's Deep was constructed in.

Peter Jackson originally filmed Aragorn fighting Sauron outside of the Black Gates during the final battle. When the filmmakers decided against this, they asked the CG animators to digitally inserted a cave troll over the actor who played Sauron.

For the original shoot, Weta Workshop designed 169 orc costumes, and the actors who wore them were trained to move in what Peter Jackson dubbed the "Full-Diaper Walk". This bothered him so much that for pick-ups 2003, he requested a complete redesign of the orcs including armour, make-up and movement, meaning that large portions of the invasion of Osgiliath, Siege of Minas Tirith, Battle of Pelennor Fields and Siege of the Black Gate had to be reshot. The new orcs (including Gothmog and the other orc captains, who weren't in the original script) are wearing matching plate steel armour with red tunics.

In the scene of Aragorn's coronation, after he and Arwen are reunited, they walk along to stand before the hobbits. The dark-haired elf maiden standing in the background (who can be seen between Aragorn and Arwen) is none other than Jane Abbott, Liv Tyler's (Arwen) riding-double.

The Cirith Ungol stair ledge was built as a wet weather set on the squash court in a hotel in Queenstown. In November of 1999, Sean Astin's (Sam) close-ups were shot in the taping of the first RotK shots, and as a side note Andy Serkis (Gollum) had not been cast yet. The set remained standing on the squash court and as things would go, it wasn't until a year later on November 30th, 2000, that Elijah Wood's (Frodo) first close-ups were actually shot on that ledge.

Apparently Elijah Wood (Frodo) and Sean Astin (Sam) portrayed the special relationship between Frodo and Sam so touchingly that the editors of the movie made a video clip of footage of the two characters together and set it to the song "I Got You" by Sonny and Cher.

Another "Wilhelm" scream can be heard when Legolas is climbing the Oliphaunt and throws one of the Haradrim off.

It always seemed illogical that when Faramir and his men were under attack by the Nazgul and retreating to Minas Tirith, Gandalf galloped out of the city to rescue them with Pippen astride. Why carry the extra burden of a Hobbit and put him in danger? Billy Boyd (Pippen) cleared up this inconsistency on the Extended DVD commentary. The scene was originally written so that Gandalf and Pippen are actually just arriving at Minas Tirith as the soldiers fall under attack, but this was later rewritten.

When Pippin tries to light the first beacon fire, one of the guards on duty is Christian Rivers, visual effects art director for Weta Digital.