It was so named by the Mouzon mission in 1952 after a Breton noun which means "the land close to the sea".

[1][2] It extends in a northwesterly south-easterly direction at an altitude of about 1 m, over a length of about 3.7 km (2.3 mi) and a maximum width of 700 m (2,300 ft), covering around 200 ha (490 acres).

Lake Armor flows into the marine waters of the Gulf of Morbihan in the Hurley Bay.

After being raised in floating cages in the freshwater of the lake, the smolts were freed expecting they would come back as adults to their nursery place.

[8] Sedimentological surveys were carried out from 2007 in the northern part of Lake Armor to collect information on the climate changings for 1200 years.