It’s at the border between Liguria and Toscana at the confluence of the torrent Vara into the Magra river and it’s a key point to get to Emilia.
It deserves a stop just to take a walk along its streets and center, even it is rather in decadence.

A bit of history:
The first documentation dates back to 10^th century: in 981 it is mentioned as a marketplace along the Via Francigena by the emperor Otto II.
The pieve is dedicated to the protomartyr St. Stephen and in 1154 is mentioned in a document by the pope Anastasius IV (the old church was rebuilt in 18^th century).
The municipality is certified from 1202.
With the movement of the Episcopal See from Luni to Sarzana, Santo Stefano was subjugated to Sarzana even if it maintained some degree of autonomy.
For its strategical position, from 14^th to ¹⁵ century, it was a land of conquest and was ruled by the Visconti, the Fregosi and finally by the Republic of Genoa.
It was subdued by Napoleon until the Congress of Vienna when it entered the Ducky of Massa Carrara and ten the Ducky of Modena and Reggio.
In 1860 it entered the Kingdom of Sardinia and in 1861 the Kingdom of Italy.

A note:
Santo Stefano di Magra is a part of the Parco Naturale Regionale di Montemarcello-Magra.

For more info:
wikipedia: Santo Stefano di Magra
wikipedia: Pieve di Santo Stefano
wikipedia: Parco naturale regionale di Montemarcello-Magra