According to Ronald D. Moore, the show runner, the team decided to keep the Gaelic words instead of translating them to English. This maintained the first person narrative by showing Claire's inability to understand the Gaelic.
The song playing in the opening credits uses the melody of the Skye Boat Song, a song that describes the escape of Bonnie Prince Charlie from Uist to Skye after his defeat in the Battle of Culloden. Composer Bear McCreary adapted Robert Louis Stevenson's poem Sing Me A Song of Lad that is Gone to fit with Claire's time traveling journey.
Author Diana Gabaldon credits watching Frazer Hines in the Doctor Who serial The War Games (and finding him fetching in a kilt) as the inspiration for setting her first novel, Outlander, in 18th-century Scotland, and for naming the novel's male protagonist "Jamie". (However, she says that the character's surname, "Fraser", is a coincidence, as the PBS station on which she watched Doctor Who habitually cut off the episode's credits, so she did not learn Frazer Hines' name until several years after Outlander was published.) Hines would later go on to play Sir Fletcher Gordon in the episode Wentworth Prison.
Doune Castle was used as Castle Leoch. The castle is famous for being featured in Monty Python and the Holy Grail. It was also used as Winterfell in Game of Thrones. The castle is located in the village of Doune, near Stirling.
The "guillotine" referred to in the series is actually "The Maiden", a Scottish precursor to the French beheading machine. During execution, victims actually faced up toward the blade - as opposed to being face down in the guillotine. The Maiden was used from 1564 up to 1710. Over 150 people had been executed with this device. The guillotine did not begin to be used in France until 1789.
In the episode Both Sides Now, Hugh Munro gives Claire the wedding gift of a dragonfly in amber, as he does in the first book of the Outlander series. The second book in the series is titled Dragonfly in Amber.
When Laura Donnelly auditioned for the part of Janet "Jenny" Fraser, she found an old schoolmate would be her partner, Sam Heughan. They had previously attended acting school together. Later they would play sister and brother, Janet and Jamie Fraser.
Several actors in Outlander have also appeared in Game of Thrones. Tobias Menzies (Frank/Jack Randall) plays Edmure Tully. Clive Russell (Lord Lovat) played Brynden Tully. Duncan Lacroix (Murtagh Fraser) played a Karstark soldier. Diana Rigg, who appears in a clip of the television series The Avengers at the start of the episode "Dragonfly in Amber," plays Olenna Tyrell.
Season 3 will include several Easter Eggs in it according to Matt Roberts and Costume Designer Terry Dresbach. Dresbach revealed at the Thru The Stones convention, a costume worn in an earlier season will be repurposed and worn by another character.
The trivia item below may give away important plot points.
In this show, Frank Randall, played by Tobias Menzies, was part of MI6, the British intelligence agency during WWII. In a BBC TV show called The Night Manager (2016), Tobias Menzies also plays the role of an MI6 agent in the 21th century.