[2] The province was established in 1815, within the Kingdom of Lombardy–Venetia, combining the valleys of Valtellina, Valchiavenna and Bormio.

After the fall of the Western Roman Empire, it came under the control of the Lombards and was first ruled by feudal lords from the local area.

Upon the collapse of the Duchy of Milan, rule over Sondrio was exercised by the Swiss Canton of Graubünden.

One of the main comuni (municipalities) is Livigno (1,800 m above sea level), which is a tourist centre in the summer and a ski resort in the winter.

[4] The economy is based on construction, logging, quarrying, tourism and light industry.

It has been necessary for farmers to engineer terraces on the steep slopes, building dry stone retaining walls and moving earth to make the best use of terrain that is unsuitable for general agricultural purposes.