ancient Sumerian city south of modern Ur (Tall al-Muqayyar), Iraq. Eridu was revered as the oldest city in Sumer according to the king lists, and its patron god was Enki ( Ea), “lord of the sweet waters that flow under the earth.” The site, located at a mound called Abū Shahrayn, was excavated principally between 1946 and 1949 by the Iraq Antiquities Department; it proved to be one of the most important of the prehistoric urban centres in southern Babylonia. Founded on sand dunes probably in the 5th millennium BC, it fully illustrated the sequence of the preliterate Ubaid civilization, with its long succession of superimposed temples portraying the growth and development of an elaborate mud-brick architecture.

The city continued to be occupied to about 600 BC but was less important in historic periods.