ancient city in the Diyālā River valley lying about 20 miles (32 km) northeast of Baghdad in east-central Iraq. The excavations carried out by the Oriental Institute of the University of Chicago revealed that the site was occupied sometime before 3000 BC. The city expanded throughout the Early Dynastic Period, and during the 3rd dynasty of Ur the city was the seat of an ensi (governor). After the collapse of Ur, Eshnunna became independent but was later conquered by Hammurabi, king of Babylonia. During the next century the city fell into decline and may have been abandoned.