A village on the Shire's eastern border, built on the banks of the river Brandywine. It lay at the southern end of the Causeway that ran southward from the Brandywine Bridge through the boggy Marish region of the Eastfarthing. Deephallow lay a little way northward of the point where the river Shirebourn met the Brandywine. At that point there was a landing place for boats, the Mithe, from which the Mithe Steps led up towards the village of Deephallow.

Directly eastward from Deephallow across the Brandywine, the Bucklanders' Hedge of the High Hay reached its southern extent at Haysend. At that point another river, the Withywindle, flowed into Brandywine out of the Old Forest. This meant that Deephallow saw two tributary rivers (the Shirebourn and the Withywindle) both empty into the Brandywine on the fringes of the village. Because of these inrushing rivers, the land southward of Deephallow formed a wide region of wetland, the Overbourn Marshes.

The Shire-hobbits who inhabited Deephallow are not described but, given that they lived in an outlying part of the Marish, they were likely of the same stock as the other Hobbits who lived in the same region. These were people descended from the Stoors, sturdy and broad of build by Hobbit standards, and adapted to living in the wetlands by building above ground rather than making Hobbit-holes.