Mamre
Archimandrite Nikifor’s Biblical Encyclopedia
(firm) (Gen 18:1) — the name of a valley, probably taking its name from Mamre the Amorite, brother of Eshcol and Aner, an ally of Abraham (Gen 14:24). The location of Mamre is indicated in connection with Machpelah (field and cave) in the following words: “And the field of Ephron, which was in Machpelah, which was before Mamre” (Gen 23:17; 25:9; 49:30). This was, of course, not the name of a city, but of a field or farm, though elsewhere in Genesis it is also identified with Hebron itself, since it lay close by.
In all likelihood there stood upon it a grove adjoining this valley, with the historically famous oak of Mamre. Here Abraham dwelt for a long time, and here he died; Isaac also lived here, when Jacob returned from Padan-aram. We may therefore reasonably regard the valley of Mamre as a particular dwelling place of the Hebrew patriarchs, in which they lived, died, and near which they were buried. Near the grove of Mamre, as is known, occurred the appearance of the three angels in the guise of travelers to Abraham, and to this day there still grows on this spot an enormous and most ancient oak (belonging to the Orthodox Palestinian Russian Mission) — a most remarkable relic of deep antiquity, namely of that very grove in which the patriarchs once dwelt.