From the Official Australian Military History of WWII

“Between the Italian Army and the Nile delta lay 240 miles of desert which received only  enough rain to support scattered clumps of low, spiny scrub. Its surface consisted generally of fine clay subsoil, often sprinkled with stones ; here and there were patches of fine sand .

From the Egyptian side a railway reached out into the desert as far as Mersa Matruh, an ancient seaport town of about 6,000 people, and thence a bitumen road travelled west to the village of Sidi Barrani.

From Sidi Barrani an earth road continued to Salum, a small harbour near the Italian frontier. There the 600-foot escarpment, which, to the east, lay generally twenty or thirty miles from the coast, touched the sea .

West and south of Salum this escarpment was climbed by two principal tracks leading into Cyrenaica,  One mounting the escarpment above Salum to Fort Capuzzo and the other travelling through the Halfaya Pass, six miles south of the port .

Along the frontier, from the sea coast to the edge of the Great Sand Sea south of Giarabub, the Italians had erected barbed wire entanglements twelve feet wide whose principal object was to enable them to control the Bedouin caravans.

On the Italian side a first-class road ran from the settled and fertile area near Benghazi to Fort Capuzzo . However, lack of water rather than lack of roads and railways was likely to impede military movement in the intervening desert.

Between Mersa Matruh and Tobruk, seventy miles within the Italian frontier, there were few wells, and their capacity was limited. Around the railhead and water supply of Mersa Matruh the British Army had, since 1939, been digging and wiring a strong system of defences.

The Italians on their side had built two elaborate fortresses, one an arc of strong posts round Bardia on the coast just across the frontier ; the other round Tobruk.”