California Doubling: The harsh winters of Minnesota (disproportionately represented in the show) were actually filmed in Simi Valley, California. The geography is clearly more California-like, as well. Southern Minnesota is generally greener and has no mountains, as shown in the episode "The Lord is My Shepherd."
Creative Differences: Initial producer Ed Friendly wanted the series to remain true to the books, but Michael Landon was against the idea of cast members going around barefoot in the wild - and of sporting the enormous beard Charles had in the books (neither he nor NBC wanted to hide his face from his fans). Thus, although every episode was "An NBC Production In Association With Ed Friendly," it's clear who the real man in charge was.
He Also Did: Rose's friend and the writer of the "Rose Years" book series, Roger Lea Mac Bride, ran for President under the Libertarian Party ticket.
Mean Character, Nice Actor: Katherine "Scottie" MacGregor, who was easily the sweetest woman of all of the female leads, highly respected and beloved by all. Nothing at all like her haughty, mean, snobbish Mrs. Oleson character.
One Steve Limit: Unmentioned in the book is the fact that Almanzo had a third sister, also named Laura. To avoid confusion with protagonist Laura Ingalls, Laura Wilder was omitted from the books and replaced by Eliza Jane. (In Real Life, and for much the same reasons, Almanzo nicknamed Laura Ingalls "Bess" for her middle name of Elizabeth.)
The Other Darrin: Bonnie Bartlett played Grace Snider Edwards in seasons 2 and 3. When the character appeared for one episode in season eight, she was played by Corinne Camacho.
In the same season eight episode, David Kaufman played Carl Sanderson Edwards, when the character had been played by Brian Part during the second and third seasons.
Woody Eney played Almanzo's brother Royal Wilder in "The Nephews" in season seven. When the character returned in "Times Are Changing" in season nine, he was played by Nicholas Pryor.
Playing Against Type: The man who played the antagonist in the final TV movie, James Karen, had played a similar role in Poltergeist. But to generations of people in the New York metro region, he was known as "Mr. Pathmark", as for many years he worked for the now-defunct Pathmark supermarket chain in their TV commercials. So Pathmark got flooded with letters from people, asking how they could employ the heartless man who tore down Walnut Grove to sell them groceries- apparently not grasping that he was just an actor.
Science Marches On: Mary's blindness is blamed on scarlet fever in the books. Modern studies suggest that she had contracted meningoencephalitis, a type of brain inflammation, which caused her blindness. The 'scarlet fever' diagnosis was probably a misdiagnosis, common back then.
And the "fever 'n' ague" everyone comes down with in Indian Territory is blamed on bad watermelons by Ma and Mrs. Scott and on "breathing the night air" by Pa, but by the end of the chapter both theories have been proved wrong and the book explains, "No one knew, in those days, that fever 'n' ague is malaria, and that some mosquitoes give it to people when they bite them."
Serendipity Writes the Plot: When the series started, the show's producer had signed an agreement that when the show ended, the site of the town would be returned to its original state. When filming the series finale, they were faced with the cost of demolishing the buildings. Michael Landon had the idea of blowing them up with dynamite, making them easy to haul away. He then wrote the memorable final scene where the townsfolk blow up their own town to accommodate the real-life demolition.
Technology Marches On: Although filmed in the 1970s and 1980s, these stories – set 100 years earlier – give viewers a representation at some of the early workings of technological marvels of the Age of Invention, as the 1870s and 1880s were arguably an era where discovery and invention was at its peak. Everything from "talking machines" (an early-type sound recorder that can replay the human voice) to the telephone is seen in its earliest forms. Additionally, although it has nothing to do with technology so much, a form of the trope can apply to sports-related episodes; as such, viewers can see an 1870s-form of baseball, football and professional wrestling, all of them novel during the post-Civil War era.
Written-In Infirmity: Alison Arngrim broke her arm right before filming of the episode "Bunny" was to begin. Since her character, Nellie, was injured in the episode anyway, the broken arm was incorporated into the script as an additional injury. Arngrim wore nineteenth-century style wrappings to cover her very real 1970s cast.
Averted in the episode "Be My Friend". Melissa Gilbert had broken her arm, but shawls and camera angles were used to hide the cast.
Matthew Laborteaux (who plays young Charles in flashbacks) later plays the Ingalls' adopted son, Albert.
Kyle Richards played Recurring Character Alicia Sanderson-Edwards and guest character Samantha Harper.
E.J. Andre played a whopping five different characters. He played Amos Thoms in "His Father's Son", Mathew Simms in "Going Home", Zachariah in "Gold Country", "St. Peter" in "The Godsister", and Jed Cooper in "The Lost Ones" and "Uncle Jed".
William Schallert played Snell in "Centennial" and Russell Harmon in "The Preacher Takes A Wife".
Katy Kurtzman played Anna in "The Music Box" and Young Caroline in "I Remember, I Remember".
Jack Ging played Marshall Anders in an early episode "Survival". He would later go on to play Willie Oleson's father-in-law in "May I Have This Dance".
Cletus Young played antagonist Harlan in both parts of "As Long As We're Together" and Cole Parker in "Goodbye, Mrs. Wilder"
Leslie Landon played the recurring role of Etta Plum (the town teacher after Laura) toward the end of the series, but also appeared in earlier seasons as Laura's fellow dishwasher Pam in "A Wiser Heart" and the pregnant woman riding in the ill-fated carriage with Mary in "The Third Miracle."