Green Hill

Green Hill (グリーンヒル) is a location that appears in the anime series Sonic X and its comic series published by Archie Comics. It is a highly forested area on Sonic the Hedgehog's home planet with a cozy village of houses scattered across it.

New World Saga
Green Hill was first mentioned by Cream as the place where she lived before arriving on Earth while conversing with an old human woman.

Homebound Saga
Upon everyone's return to Green Hill, except for Sonic, Amy spent a few nights living with Cream and her family as opposed to living in her own house.

During this time, Eggman came by during the night looking for Sonic, frustrating Amy enough make her to take out her anger on the Grand Egg Imperial by hurling Piko Piko Hammers at it. Eventually, Tails showed up and engaged Eggman in battle as well, only to be overwhelmed by Eggman’s powerful homing missile. Fortunately, Super Sonic appeared in time to save Tails and blow the Grand Egg Imperial up in the skies above Green Hill. Super Sonic then went to Amy’s house, where he returned to normal. Amy, with tears in her eyes, confronted Sonic with how worried and saddened she was over the idea of losing him, and had even planned on waiting for him forever. In response, Sonic offered her a rose, prompting Amy to hug him.

Metarex Saga
Six months later, while Tails, Cream, and Amy were watching a meteor shower in Green Hill, Cosmo arrived, crash landing in the area. After being nursed back to health by Cream, Amy, and Tails, she left the house upon hearing a Metarex nearby. After some time and learning of the Metarex’s goals from Cosmo, the group decided to use Tails’ Blue Typhoon to go to space and stop the Metarex’s plans.

Archie Comics
When Dr. Eggman trapped Sonic and his allies in a virtual reality, Sonic found himself in a retro version of Green Hill. Making his way through this strange world while adjusting to its physics, Sonic came across a digital version of Eggman and defeated him. As he set some critters lose though, Sonic was transported to the next level.