There were originally supposed to be eighteen episodes.
After the opening titles in each episode, a distant train horn can be heard. The boys meet this train in episode nine, "Chapter 9: Into the Unknown".
In episode two, "Chapter 2: Hard Times at the Huskin' Bee", Gregory (Collin Dean), Wirt (Elijah Wood), and Beatrice (Melanie Lynskey) pass through Pottsfield, a town full of skeletons. This is a portmanteau of Potter's Field, a term for a graveyard for people who can not afford to buy a burial plot.
The phase of the moon in the show was meant to match up with the phase of the moon on the night each episode originally aired.
All of the names that Gregory (Collin Dean) names his lucky frog (Jack Jones) are: Kitty, Wirt, Wirt, Jr., George Washington, Mr. President, Benjamin Franklin, Dr. Cucumber, Greg, Jr., Skipper, Ronald, and Jason Funderberker.