This is our own personal chronological timeline for Sonic the Hedgehog and his universe, created and researched by the Sonic Metropolis Team. We spent many hours, days, and even months to figure out which timeline could be the most canon and logical one we can make. Keep in mind though that it is not perfect, because we also came to the conclusion that creating a 100% true Sonic timeline is impossible, because there will be always little details or facts which will speak against this timeline. However, this does not stop us from making the most logical timeline we can offer.
You also need to keep in mind that not all games or cartoons can be always canon of course, so we also sorted games out which are canon, and which are not. Furthermore we will not include Mini-, Party- or mobile games just as all other different sonic game versions ported from the one console to the other, and same for national changed versions [We always pick the original JAP variant]. If you however disagree with something, or you think you might found some issues with our timeline, you can always contact us about that on discord where we could discuss about what we might missed then.
Team Sonic Metropolis