Meereen is the northernmost and greatest of the three great city-states of the Bay of Dragons, north of Yunkai and Astapor. It is located at the mouth of the Skahazadhan River, which flows from its origins in Lhazar through the mountains separating Meereen and the rest of Slaver's Bay from the Red Waste. The Dothraki Sea lies to the north, beyond the river. The wealthiest residents live in pyramids.
People and things from Meereen are known as "Meereenese".
(source GOT wiki)