The mountain owes its name to its geographical location. Its summit marked, in fact, since the Middle Ages, the meeting point of the border lines of three states: the Republic of Venice (to which the Camonica Valley belonged), the Grisons (of which the Valtellina was part until the 18th century) and the territory under the jurisdiction of the Episcopal Principality of Trento (i.e. the Val di Sole).
Even today, on the top of the Corno meet the provinces of Brescia, Sondrio and Trento, whose current borders are the same as those of the ancient states.