End-World is the furthest region of All-World. The Dark Tower lies within End-World and thus Roland must cross through this dangerous land to reach the tower. End-world is made up of several different distinct regions.
End world includes Thunderclap, the dark land inhabited by Taheen and Can-toi where the Devar-toi complex is. Thunderclap Station, where the captured children of the Calla Bryn Sturgis are taken is also in this land. Thunderclap also holds Castle Discordia which holds hundreds of rooms leading to different worlds.
Beyond Thuderclap lies the Discordia Badlands. The Badlands is a dark land of broken twisted tress and giant dark rooks. The Badlans also house Catle Town and the Crimson King's Castle: Casse Roi Russe. When Roland finds the castle it is but deserted with all the King's servants killed.
Finally, at the end of End World lies Can'-Ka No Rey, the huge field of Roses. A path cuts through the field of red roses and at the center of the rose field lies the nexus of the multiverse: The Dark Tower.