Mamre (ˈmæmri; מַמְרֵא), full Hebrew name Elonei Mamre ("Oaks/Terebinths of Mamre"), refers to an ancient religious site originally focused on a single holy tree, growing "since time immemorial" at Hebron in Canaan. It is known from the biblical story of Abraham and the three visitors. The tree under which he had pitched his tent is known as the oak or terebinth of Mamre. Modern scholars have identified three sites near Hebron which, in different historical periods, have been successively known as Mamre: Khirbet Nimra (a little excavated Persian and Hellenistic period site), Ramat el-Khalil (the best known site), and Khirbet es-Sibte. The last one contained an old oak tree identified by a relatively new tradition as the Oak of Mamre, which has collapsed in 2019, and is on the grounds of a Russian Orthodox monastery.
Jewish-Roman historian Josephus, as well as Christian and Jewish sources from the Byzantine period, locate Mamre at the site later renamed in Arabic as Ramat el-Khalil, 4 km north of historical Hebron and approximately halfway between that city and Halhul. Herod the Great apparently initiated the Jewish identification of the site with Mamre, by erecting there a monumental enclosure. It was one of the three most important "fairs" or market places in Judea, where the fair was held next to the venerated tree, accompanied by an interdenominational festival joined in time by Jews, pagans, and Christians. This prompted Emperor Constantine the Great to unsuccessfully attempt at putting a stop to this practice by erecting a Christian basilica there.
Mamre is the site where Abraham pitched the tents for his camp, built an altar (), and was brought divine tidings, in the guise of three angels, of Sarah's pregnancy ().
Genesis 13:18 has Abraham settling by 'the great trees of Mamre'. The original Hebrew tradition appears, to judge from a textual variation conserved in the Septuagint, to have referred to a single great oak tree, which Josephus called Ogyges. Mamre may have been an Amorite, a tribal chieftain after whom a grove of trees was named.