Continuity mistake: When Edwards is first discovered missing by Grace, the moon is in the background in the center of the screen. After all the time that goes by with Edwards in the casino, Charles looking for him, finds him and goes all the way back to where they were sleeping (figure at least an hour or more), the moon is still in the exact same position in center of screen from the exact same camera angle. In reality, the moon would have been more to the right or disappeared completely by now (depending on the timespan).
Someone Please Love Me - S5-E22
Continuity mistake: Charles walks down the staircase with a small trunk, suitcase, and a duffel bag. He finishes business from the man he bought the horses. When he walks out onto the porch, Charles is only carrying his duffel bag, and tosses it into his wagon. No other luggage is visible.
Times Are Changing (2) - S9-E2
Factual error: This episode takes place around 1886/1887 and in the episode Royal dies. In real life, Royal didn't die until 1925.
The Nephews - S7-E14
Factual error: Royal Wilder promises to give his sons an Indian Head nickel if they are well behaved at Almanzo's/Laura's house. The Indian Head nickel was not minted until 1913 - 30 to 40 years later.
The Raccoon - S1-E10
Plot hole: The plot gets confusing here. First, Laura and Jack (the dog) are rabidly bitten by Jasper (her pet racoon). The doctor warns they may have rabies from the bite. A second more dangerous raccoon is discovered which eventually left the area. In the end, Charles (discovering there were two raccoons in the barn after finding Jasper remaining), says Laura is going to be OK after all. The main confusion is that Laura would still be in danger from the bite regardless of which untested raccoon bit her.
Revealing mistake: When Carrie (played by twins) falls down in the opening sequence, it appears that she gets back up and continues running. In reality, after falling, the other twin gets up and continues. If you look closely enough, you can see that when getting up, Carrie is slightly closer towards the camera than when the first twin fell.
Factual error: A modern day fire extinguisher is shown on a beam Charles walks next to in the town of Bixby.
Factual error: When the older boys are lying around the playground discussing The Election, you can see the bottom of the boy's shoe. It is made of molded rubber and features a "tread" on the bottom. This would not be how shoes were made in that time period.
Factual error: Adam Kendall goes to Minneapolis to take the entrance exam to law school. He meets a fellow student who, after the first exam, accompanies him to the "EL (the elevated train) " Minneapolis never had an elevated train, only Chicago.
Come, Let Us Reason Together - S7-E13
Continuity mistake: By this episode, the restaurant windows have been displayed as Caroline's restaurant (replacing Nellie's). Although most scenes here correctly display Caroline's, one scene that starts from the outside with the horses riding by, the windows still display Nellie's (happens about 3 times this episode - the last time is shown just before Nellie and Percival are laughing on the bed).
The Raccoon - S1-E10
Character mistake: Charles takes a bowl of water to Jack. Jack steps away from the water, and doesn't drink. Then a couple of scenes later, when Caroline and Charles are in the barn, Mary comes out and says Laura is thirsty. Caroline starts crying and says that Dr. Baker says that it's a sign, but a sign of rabies is actually when the person or animal doesn't want water. At one point, it was called hydrophobia because of the fear of water. (00:38:26)
The Raccoon - S1-E10
Factual error: Laura and Caroline are playing a word association game about beverages and Laura says "orange juice, " which wasn't used by Americans until the 1920s. Any earlier than that, oranges were a luxury not available to farmers in Minnesota.
Christmas At Plum Creek - S1-E14
Character mistake: When Charles explains to Carrie about Christmas, he mentions 3 kings and 3 wise men. The bible refers to them as Magi or Wise Men and no clear evidence on whether there were just 3, or if they were even kings. Putting aside the number of visitors and what they were called, it's either kings or wise men, but not both.
He Loves Me, He Loves Me Not (2) - S6-E26
Other mistake: Charles has just brought Adam a letter to the site of the blind school rebuild. When Adam is told that his father died, he and Mary walk away from Charles. The terrain was very uneven. Being blind they realistically wouldn't be able to navigate it without stumbling.
A Christmas They Never Forgot - S8-E11
Continuity mistake: Every time they go outside during the blizzard, the keep talking about taking in wood, but yet the wood pile never changes throughout the whole show.
Revealing mistake: The guys get the pregnant girl and her kids 50 lbs pounds of flour. She goes outside, people are talking about her and she runs. You can see tire tracks in the dirt road.
Continuity mistake: During the final football game, the sun position changes from one side of the field (before the game starts) to the other side during most of the game then back to the first side for the last play of the game.
Quarantine - S3-E13
Visible crew/equipment: Around 9:15 when the family is sitting at the table talking, in the lower right corner the shadow of a camera person appears below Ma's chair. (00:09:14)
He Was Only Twelve (2) - S8-E22
Continuity mistake: After James is shot, Charles takes James away from the house because his family is getting upset. He builds an altar. A ladder is on the side where the shelter is. The ladder is gone in subsequent shots.
Factual error: When the man is holding onto the rope from the balloon, you can see modern tire tracks in the field.
