Ur Kaśdim (Hebrew: אוּר כַּשְׂדִּים ʾūr kaśdīm), commonly translated as Ur of the Chaldees, is a city mentioned in the Hebrew Bible as the birthplace of the Israelite and Ismaelite patriarch Abraham. One of the traditional sites of Abraham's birth is placed in the vicinity of the city of Edessa (Şanlıurfa in modern Turkey). Some Islamic and Jewish authorities, such as Maimonides and Josephus, placed Ur Kaśdim at various Mesopotamian or southeast Anatolian sites such as Urkesh, Urartu, Urfa or Kutha. In 1927, Leonard Woolley identified Ur Kaśdim with the Sumerian city of Ur, in southern Mesopotamia, where the Chaldeans were to settle in much later times, around the 9th century BCE; Recent archaeology work places the location in Nasiriyah, where the ancient Ziggurat of Ur is located.
Ur Kaśdim is mentioned four times in the Tanakh, with the distinction "Kaśdim" usually rendered in English as "of the Chaldees." In Genesis, the name is found in 11:28, 11:31 and 15:7. Although not explicitly stated in the Tanakh, it is generally understood to be the birthplace of Abraham. Genesis 11:27–28 names it as the birthplace of Abraham's brother Haran, and the point of departure of Terah's household, including his son Abram.