The best guide to Rome’s geography and maps is the river Tiber and the hills (image right). After a few thousand year’s worth of urban planning the latter have become a little difficult to distinguish in places.
From a visitor’s point of view the city is generally subdivided in such a way as to include a good mix of geography and monuments to visit, such as the Forum.
Stricter methods of subdividing the city include:
Geography, ie the river and hills. Eg Trastevere is called that because it is across the Tiber river (the “Tevere”): Trans-Tevere.
Capitoline hill – The centre of power & the point from which all roads were measured from
The Vatican – once just a hill across the Tiber river with attractions like Nero’s circus where loads of Christians got crucified. The possibility that Saint Peter might have been crucified there led to Saint Peter’s basilica being built there.
Rome is famous for its 7 hills although in fact there are a few more hills than just 7. The city originally grew on the left bank of the river Tiber and then made its way across the river to include Vatican and Gianniculum hills.
The first two hills to be populated were the Palatine and Capitoline but the city soon extended to include the Aventine, Caelius, Oppius, Viminalis and Quirinalis and others. Some of these were actually made up of a couple hills each with their own name. A curious one is “Testaccio” which is actually a hill entirely made of broken amphora pieces (the amphorae were the ceramic containers used for commerce).
In ancient Roman times the city was subdivided into numbered units called “Regio”. Augustus subdivided the city into 14 units possibly according to his own astrological birth stars (Capricorn if you’re interested).
After the empire we have the Dark Ages or early Medieval. The city’s population shrank from millions to tens of thousands who assembled near the river and literally abandoned the city around them. The 14 Regio were reduced to 12 but were then gradually increased and have become 22 “Rioni” as recently as the 20th Century as the population has reached the size it once was so long ago.
During the 18th century a good number of attractive marble plaques with coats of arms were placed to show regional limits and are still visible throughout the city. Look out for them. You may well notice a number of other plaques of various sorts including coats of arms (Rome was always a feudal system), rubbish collectors plaques placed between the 17th and 18th centuries, plaques showing the level reached during various floods of the city and a multitude of various inscriptions.
The major 14 regions are called Monti, Trevi, Colonna, Campo Marzio, Ponte, Parione, Regola, Saint Eustachio, Pigna, Campitelli, Sant’ Angelo, Ripa, Trastevere and Borgo. Each has its own coat of arms.