Bayt Umm al-Mays was situated in a mountainous area facing northwest, and was bordered by two deep wadis to the northeast and southwest which met just northwest of the village. This combination of high elevation and deep wadis on three sides conferred upon the village a degree of strategic importance. A secondary road linked the village to the Jerusalem−Jaffa highway and to the villages of Suba and al-Qastal. It was known during the Crusader period by the name "Beittelamus." The layout of the village was trapezoidal, and its older houses, which were built of stone, were clustered closely together. The newer houses extended to the southeast, towards the mountain that overlooked the village on the south. Bayt Umm al-Mays was classified during the Mandate era as a hamlet by the Palestine Index Gazetteer. Its inhabitants were Muslim. Potable water was provided by two springs southwest of the village. The agricultural economy was based on the growing of grain and fruit, particularly grapes. Crops were watered by rainfall and irrigated by water drawn from springs. Part of the village land was used as grazing areas for sheep and goats. Most of the agricultural land was south of the village, while vineyards and fruit orchards covered the mountain slopes. In 1944/45 a total of 273 dunums was allotted to cereals; 51 dunums were irrigated or used for orchards. Several khirbas were located near the site.
