Factual error: In the remastered DVD editions, on Doc Baker's wagon, you can see that the canvas wagon cover has a plastic window sewn into it.
Factual error: Aeroplane trails are in the sky throughout several episodes. This wouldn't have been possible in the time the show is set.
Welcome To Olesonville - S9-E3
Continuity mistake: Mrs Olsen cleans up the old Hansen house to sell, however it was made the blind school years back and burned down, killing Mary's baby and Alice Garvey.
Laura: I hate that Nellie Oleson.
Caroline: Laura! Don't say "hate" - don't even think "hate"! I'm sure Nellie has her good qualities somewhere.
Charles: Your ma's right, half-pint. Now on the way home, we'll try and think of some.
The Voice of Tinker Jones - S1-E11
Trivia: Sean Penn is in this episode, albeit with no lines, always wearing the same blue shirt. His father directed this episode.