Spring Yard Zone did not originate from fanon, and more information can be found on their respective wiki(s). You may read more about it on the following wiki(s):

Spring Yard Zone
Spring Yard Zone in Sonic the Hedgehog
First Appearance Sonic the Hedgehog
Notable Resident(s)
Spring Yard Zone is a location in Sonic series. It has made appearances in Sonic the Hedgehog as an urban level complete with springs and bumpers.

Fanon Appearances

Sonic Heroes 2

Spring Yard Zone makes another appearance in Sonic Heroes 2. Here, it has been renovated. and has been industrialized; on the Metropolis/Spring Yard border, there is a massive van entrance, an industrial park. This entrance is usable only once in Team Babylon's storyline.