Although the two are structurally quite different, Hadrian’s Wall and the Wall in the North are remarkably similar in terms of where they are located in their respective universes. Both of these walls took advantage of relatively narrow portions of their respective continents in order to divide North from South efficiently. In the case of Hadrian’s Wall, this placement was chosen because it allowed the Romans to completely bisect the continent by building just 73 miles of fortifications, saving them time, manpower and resources by doing so. In addition, the Romans also used the natural landscape to strengthen their defenses. They did this by constructing Hadrian’s Wall along naturally strong defensive positions like cliffs and hills wherever they could. Most notably, the central section of the Wall was deliberately made to follow the Whin Sill, an area of North-ward facing volcanic cliffs which offered a natural defensive position. This resulted in some sections of the wall being nearly impossible to assault, which benefited the Romans by shortening the length of wall that they needed to be prepared to repel an attack at.
The Wall in the North also utilizes naturally defensive terrain in Westeros in order to bolster its strength. This is especially evident in the extreme West end of the Wall, which terminates in a deep valley referred to simply as “The Gorge”. This natural defile in the land allowed the builders of the Wall to end the fortification before actually reaching the Bay of Ice, allowing them to presumably save time, manpower and resources by doing so. The Wall also takes advantage of its position in the North of the continent, the temperature of which allowed the use of massive slabs of ice to construct the fortification instead of stone or wood.
 Patricia Southern, Roman Britain: A New History 55 BC-AD 450 (Gloucestershire: Amberly Publishing, 2011), 172.
 David J. Breeze and Brian Dobson, Hadrian’s Wall (London: Penguin Books Ltd., 1977), 30.
 George R.R. Martin, The World of Ice and Fire (New York: Bantam Books Ltd., 2014), 474.