The Gorner Glacier (German: Gornergletscher) is a valley glacier found on the west side of the Monte Rosa massif close to Zermatt. It is about 12.4 km (7.7 mi) long (2014) and 1 to 1.5 km (0.62 to 0.93 mi) wide. The entire glacial area of the glacier related to Gorner Glacier is 57 km2 (22 sq mi) (1999), which makes it the second largest glacial system in the Alps after the Aletsch Glacier system. Numerous smaller glaciers connect with the Gorner Glacier. Its (former) tributaries are (clockwise on this map): Gornergletscher (after which the whole system is named, but the upper part is almost disconnected from the lower part nowadays), Monte Rosa Gletscher, Grenzgletscher (nowadays by far its main tributary), Zwillingsgletscher, Schwärzegletscher, Breithorngletscher, Triftjigletscher, and Unterer Theodulgletscher (although the last three ones are actually disconnected now).