Continuity mistake: In Bag End, as Gandalf goes towards the table with the map, the window bench to the left can be seen. On it lies a red blanket folded up up nicely. Later, when Bilbo is at the window looking out at the Sackville-Bagginses, the blanket isn't folded as it was before, and the book near the blanket has the papers on/near it arranged differently as well.
Continuity mistake: The Troll hasn't even entered the doorway yet, and both Sam and Aragorn look way up, as if the Troll were standing right in front of them already, but the Troll is only visible more in the distance, through the door. Since the Troll is still only in the doorway for them to see, the eye angle should still be towards the doorway, not up over them. Then when the Troll smashes through the doorway, and walks towards Sam, in the same shot as earlier, Sam looks way up at the Troll, but this time the eye angle is correct.
Continuity mistake: There's a shot of the back of Gandalf's wagon as he rides into the Shire. A scarf is on a lantern at the right side of the wagon. Gandalf sings the lines "The Road goes ever on and on, down from the door..." The next shot, a view of the wagon from the front, and the scarf is on the lantern at the left side of the wagon. The scarf switched sides because the first shot is flipped.
Continuity mistake: When the Balrog's whip wraps around Gandalf's ankle and pulls him off the bridge in Moria, you can see that the surface of the bridge where he was standing is perfectly flat and smooth. We cut to Frodo screaming, then back to Gandalf, who is now hanging onto an easy-to-grip groove in the rock.
Continuity mistake: As Gimli runs into the room of Balin's Tomb, he stops and says, "No!" and in this wide shot, the huge stone with skeletal remains on and around it is lying away from the wall, just behind Gimli, to his left. He kneels, and after he cries, "Oh no! No!" there is a wide overhead shot of the room. In this shot, that particular stone with the skeletal remains is right next to the corner of the wall now. This doesn't have anything to do with camera angle.
Continuity mistake: When Gandalf is facing off with the Balrog on the bridge, he is seen from a wide camera angle as having his illuminated staff directly in front of him. When the camera angle switches to a close up, the staff is no longer in front of him. The camera angle changes to a wide view and the staff is seen in front of him again.
Continuity mistake: During the Prologue, after Sauron has swept some of the men away with his mace, Elendil (Isildur's father), brings up his courage and charges towards Sauron. Sauron quickly hits him with the mace and sends him flying towards the wall. His helmet is still on his head, although one side of it is drastically bent from the impact. Then, with a horrified look on his face, Isildur rushes up to his crushed father. When Isildur holds his father's head in his hands, Elendil's helmet is on his left. Isildur wouldn't have had time to take it off himself as the camera follows his moves and shows him falling to his knees before his father's still form.
Continuity mistake: As Sam is getting into the boat, in Lorien, you see Boromir's body (not head) on the right of the screen and Aragorn's body (not head) to the left. All three including Sam, are wearing the cloaks they received in the scene before. While Sam gets into the boat, the voice-over you hear in these few shots is Celeborn, who is actually talking to Aragorn on shore. Then in the next shot of Aragorn talking to Celeborn, Aragorn isn't wearing his cloak, as he's receiving the knife gift from Celeborn. The next problem is, while Merry and Pippin talk about Lembas, Boromir is in the background without his cloak. In the next shot when Sam gets into the boat, in the background we see Boromir's body with the cloak on again. Next we see Aragorn still talking to Celeborn on shore, in the background we see Boromir and he's not wearing the cloak yet again. The shots were obviously put together out of sequence, and none are flashback.
Revealing mistake: At Rivendell when Frodo puts the Ring on the stone table in the middle and then Gimili says his, "I'd rather die than see the Ring in the hands of an Elf" Gandalf stands up an makes a sort of "you're out- like an umpire" move at someone while they are all arguing, when the camera is on the people. When they go to the reflection on the Ring, Gandalf makes the movement again. Clearly it is the same shot again.
Continuity mistake: During the end fight scene with the Uruk-hai, the fight scene takes place on the side of a hill for the most part, but you can see that sometimes the sunlight shines down the hill and sometimes it shines across the hill, meaning it was filmed at different times of the day.
Revealing mistake: After Bilbo returns from the party invisible and finds Gandalf by the fireplace, look at Gandalf as Bilbo walks between him and the fire. There is no shadow cast on him when there clearly should be. Also as the camera pans round following Bilbo's movements, you can see Gandalf is casting a shadow on the floor but not on the table, but when Bilbo walks up to it he does, even though Gandalf is between him and the fire light.