Schwarzsee is a lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 at Zermatt

Zermatt

Zermatt is a municipality in the district of Visp in the German-speaking section of the canton of Valais in Switzerland. It has a population of about 5,800 inhabitants....

 in the canton of Valais

Valais

The Valais is one of the 26 cantons of Switzerland in the southwestern part of the country, around the valley of the Rhône from its headwaters to Lake Geneva, separating the Pennine Alps from the Bernese Alps. The canton is one of the drier parts of Switzerland in its central Rhône valley...

, Switzerland

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

. It is located below Matterhorn

Matterhorn

The Matterhorn , Monte Cervino or Mont Cervin , is a mountain in the Pennine Alps on the border between Switzerland and Italy. Its summit is 4,478 metres high, making it one of the highest peaks in the Alps. The four steep faces, rising above the surrounding glaciers, face the four compass points...

 at an elevation of 2,552 m.
Its surface area is 0.5 ha. A chapel dedicated to Mary of the Snows

Dedication of Saint Mary Major

The Dedication of Saint Mary Major, previously known as Dedicatio Sanctæ Mariæ ad Nives , is a liturgical feast day celebrated on August 5 in the Latin Rite of the Catholic Church. In the Roman Catholic calendar of saints it has the rank of optional memorial, and in the General Roman Calendar of...

 borders the lake (Kapelle "Maria zum Schnee").
The lake lends its name to the mountain ridge

Ridge

A ridge is a geological feature consisting of a chain of mountains or hills that form a continuous elevated crest for some distance. Ridges are usually termed hills or mountains as well, depending on size. There are several main types of ridges:...

(2,583 m) above (45°59′29"N 7°42′35"E). It can be reached by cable car from Zermatt.