Ur, often referred to as Ur of the Chaldees (Ur Kasdim), was a major Sumerian city-state during the early 2nd millennium BC. It was located in southern Mesopotamia, close to the Euphrates River. It is noted in the Bible as the birthplace of the patriarch Abraham .
The land where Ur was located in was probably first populated by the Semites. Its foundation is sometimes attributed to Arphaxad or his direct descendants. Around the time of the events at the tower of Babel or shortly after, an advanced civilization inhabited there, and Ur quickly became a major urban center on the Mesopotamic plain, noted by its luxury and wealth, and a commercially strategic port because of its proximity to the Euphrates and the Persian Gulf. Ur experienced a significant development, establishing a city-state with its own monarch. The inhabitants of Ur practiced pagan religions. The patron deity of the city was the Sumerian-Akkadian moon god known as Nanna.
Abram's family was established in Ur, and he, along with his brothers Nahor and Harran, was born there to Terah. He also likely married Sarai while living in Ur . At some point, however, Terah took his family and left Ur, setting out for Canaan. It's thought that Terah's departure from Ur was due to religious reasons as his conversion to Yahwism conflicted with the polytheist beliefs of the Sumerians.
Yahweh later reminded Abram that he took him out of Ur of the Chaldees to give him possession of the land of Canaan .