The island's shore is deeply indented with two deep bays on both sides of a narrow 1.2 km wide isthmus that joins the northern from the southern part of the island.

Ostrov Bol'shoy, a fairly large island with a diameter of 3 km, is located in the eastern bay.

[2] Geologically Kolosovykh Island is part of the Minina Skerries a coastal archipelago forming a complex structure that includes the Plavnikovyye Islands further south.

The highest point of the island is 85 m high Gora Kolosovykh Hill.

This island belongs to the Krasnoyarsk Krai administrative division of Russia and is part of the Great Arctic State Nature Reserve, the largest nature reserve of the Russian Federation.