Deephallow was a village on the Shire's eastern border, built on the banks of the River Brandywine, just north to the point where Shirebourn flowed into the river. Immediately across Brandywine was Haysend, the southernmost point of Buckland.
David Salo suggested that the name represents a speculative Old Hobbitish form *Deophealh "deep haugh". A haugh meant first "angle, corner, secluded place" and later "land by a river", consistent to the location of the village near the wedge formed by Brandywine and Shirebourn. The same element is also seen in "Woodhall".