The lake is 117–119 metres (384–390 ft) above sea level, and is regulated at the Kaitakoski power plant in Russia.

The best-known islands of the lake are Hautuumaasaari ("Graveyard Island"), which served as a cemetery for ancient Sami people, and Ukonkivi ("Ukko's Stone"), a sacrificial place of the ancient inhabitants of the area.

It empties northwards through the Paatsjoki at the mouth of the Varangerfjord, which is a bay of the Barents Sea.

The lake depression is a graben bounded by faults active in the Cenozoic.

[3] On 28 December 1984, a Soviet guided missile crashed into the Lake Inari.