Ondu is a continent in the southwestern quadrant of Zendikar that juts into the Silundi Sea. The continent shows signs of influence from ancient civilizations, but it is nature that dominates here, taking precedence over small settlements of humans, kor, goblins, and merfolk.

The geography of Ondu is dominated by a sense of sweeping verticality. The precarious Makindi Trenches, the skyscraping trees of the Turntimber, and the depths of the Crypt of Agadeem all contribute to the strange sensation that travel in Ondu occurs up and down rather than east and west. Jwar, the Isle of Secrets lies near the southern coast. Huge granite heads loom half-buried in the earth, and a beam of pure blue light can be seen shooting straight up out of the island. But no explorer has yet uncovered the source of the light.

The region of Ondu is composed of one central landmass and the three major islands off its coast: the large, southernmost island of Agadeem, the smaller, temperate Beyeen, and the tiny, sea-swept Jwar.

The continent of Ondu is a vast plateau crisscrossed by deep trenches and meandering rivers.