In the English-language manual of Sonic CD for the Sega CD, Amy Rose is credited as Princess Sally, in an attempt to support the SatAM TV series (though the PC version and all later games called her Amy).

Sonic was the first of two video game characters to appear in the Macy's Day parade. (The second was Pikachu from the Pokemon franchise.)

In Japan, Sally was known by both her real name and a nickname of hers called "Ricki". This never made its way to America.

Amy is the first fully clothed character that was not evil.

In "Total Chaotix", the first story to feature Charmy (Sonic the Comic #53 to #58), Charmy's name was spelled "Charmee"

Vector and Espio are the first reptilian characters in the entire series.

The name Tikal is based on a temple in Central America also named Tikal, which is similar to the Temple in the Mystic Ruins.

By mistake, Rotor was referred to as Boomer in the earliest issues of the comic book. It was corrected in issue #6, as well as reprints for these early stories. It was explained that "Boomer" was actually a nickname the character had in his childhood; some stories depicting the Freedom Fighters in their childhood even have him addressed as Boomer.

Espio has the most playable appearance of all the Chaotix Members, with Vector at second, and Charmy in third.

Mighty's name was misspelled "Mighity" in the Japanese manual for Chaotix. This is perhaps a direct result of errors in translation.

In the prototype of Knuckles Chaotix, dubbed in the thought-to-be ROM form as "Sonic Crackers", Sonic the Hedgehog was originally playable along with Miles "Tails" Prower. Sonic's movements and standing animations are exactly the same as Mighty's, thus leading to the belief that Sonic was taken out of Knuckles Chaotix fairly late in game production and got replaced by Mighty.

The only Main Sonic games that Tails has not appeared officially in since Sonic the Hedgehog 2 were Sonic CD and Sonic Labyrinth; additionally, the only Sonic cartoon Tails was not ever featured in was Sonic Underground.

The majority of the Sonic cast from the games have made appearances in Archie's Sonic the Hedgehog comics, with the exception of Cream, Cheese and Vanilla.

Charmy is first hero male in the official Sonic continuity who wears a shirt.

Issue 2 of the original 4-issue mini-series featured a splash page artwork of the Freedom Fighters battling Robotnik's robots, with Bunnie already included in their ranks. But her coloring scheme and overall design was different from both her SatAM counterpart and her future appearance in the comic. This page (along with every other filler page: most of them non-canonical gag panels) was not reproduced in the Sonic The Hedgehog: In The Beginning trade paperback.

Sonic is the fastest character in the series but yet Amy can catch up with him even when she’s carrying her hammer no matter the size. This could be ether Sonic is just going slow for her or she practiced running as fast as Sonic.

Blaze is the only female character in all portrayals of Sonic the Hedgehog to have a super form. She is also the only female shown to use Chaos Control.

Sonic was the first of two video game characters to appear in the Macy's Day parade. (The second was Pikachu from the Pokemon franchise.)

Sonic's first appearance in games wasn't in Sonic The Hedgehog, But in the 1990 arcade game RAD MOBILE as an air freshener.

Former comic writer Ken Penders has intended to have Sonic's full name as "Olgilvie Maurice Hedgehog". On Sonic's Data File page, it leaves his first name a mystery, as Penders intended to have his first name mentioned later on. This plot idea never came to be however, as Penders left the comic staff after issue #160. Thus, Sonic's first name is still not actually Sonic, but his true first name remains unknown.