The Regions are given as they were laid out by Fiorelli, the boundaries being marked by broken lines. The Insulae are designated by Arabic numerals.
Stabian Street, between Stabian and Vesuvius gates, separating Regions VIII, VII, and VI, from I, IX, and V, is often called Cardo, from analogy with the cardo maximus (the north and south line) of a Roman camp. Nola Street, leading from the Nola Gate, with its continuations (Strada della Fortuna, south of Insulae 10, 12, 13, and 14 of Region VI, and Strada della Terme, south of VI, 4, 6, 8), was for similar reasons designated as the Greater Decuman, Decumanus Maior; while the street running from the Water Gate to the Sarno Gate (Via Marina, Abbondanza Street, Strada dei Diadumeni) is called the Lesser Decuman, Decumanus Minor.
The only Regions wholly excavated are VII and VIII; but only a small portion of Region VI remains covered.
The towers of the city wall are designated by numbers, as they are supposed to have been at the time of the siege of Sulla, in 89 B.C.