The Forest of Leota

This is a forest south of Ponyville which the mane six had to cross to get to the Changeling Kingdom in "The Return of Queen Chrysalis". The Changeling Kingdom had a different location than in season six.

It is not specified how close is the Changeling Kingdom to this forest, but the mane six has to get through it to get to the Kingdom, and the map shown in the comics doesn’t go too far from that forest. That’s why I believe the Changeling Kingdom was around the Forest of Leota.

Later, the Changelings are defeated by the mane six and imprisoned for 1000 years (though they escape later by tricking Twilight into opening the door to give them a book...). After that I believe they settled their new kingdom to where it is now.

The grifix lived in this forest for a long time, until the changelings, a new born species (if you wanna know how they were born read “My Little Pony: FIENDship is Magic” issue 5), decided to build their kingdom near that forest. The Grifix though they could keep living there even with that dangerous species around, and so they did so for around 100 years. They soon found out that the changelings could sense the love from the grifix, even though they couldn’t see them (that’s also why they couldn’t turn into them - they can’t turn into something they don’t know how it looks). The changelings killed many grifix but the remaining grifix were too afraid to leave (the forest was their home for a very long time). After a while they all felt that they couldn’t live anymore with the constant fear of being killed by a changeling. They were too afraid to go hunt and they were starving. That’s when Queen Starla decided that they couldn’t go on anymore. She gathered her grifix and they all left the forest, in the search of a new, safe, home.