The Magra (Macra), in ancient times the boundary between Liguria and Etruria, may be considered as constituting on this side the limit of Northern Italy.
The ninth region comprised Liguria, extending along the seacoast from the Varus to the Macra, and inland as far as the river Padus, which constituted its northern boundary from its source in Mount Vesulus to its confluence with the Trebia just above Placentia.
In the division of Italy by Augustus it formed the seventh regio and extended as far north as the river Macra, which separated it from Liguria.
Its position at the entrance to the valley of the Magra (anc. Macra), the boundary between Etruria and Liguria in Roman times, gave it military importance in the middle ages.
The Ligurian Apennines extend as far as the pass of La Cisa in the upper valley of the Magra (anc. Macra) above Spezia; at first they follow the curve of the Gulf of Genoa, and then run east-south-east parallel to the coast.