The province is divided into four communes (comunas) administered by four municipalities: According to the 2002 census by the National Statistics Institute (INE), the province spans an area of 10,131.6 km2 (3,912 sq mi)[1] and had a population of 81,681 inhabitants (41,578 men and 40,103 women), giving it a population density of 8.1/km2 (21/sq mi).

This area is within the narrowest part of Chile, where the Andes meet the Coastal range.

The small valley consists of two sectors, Illapel and Salamanca.

There are no wineries in any of these sectors, but vines planted on the rocky, foothill soils produce small quantities of high quality Syrah and Cabernet Sauvignon grapes with high acidity and low pH, which is increasing the interest for the area among many wine producers.

[4] Only one brand of wine, De Martino Syrah, currently holds the D.O.