Ust-Bolsheretsky District (Russian: Усть-Большере́цкий райо́н) is an administrative [1] and municipal[4] district (raion) of Kamchatka Krai, Russia, one of the eleven in the krai.

It is located in the southern and southwestern parts of the krai.

The area of the district is 20,626 square kilometers (7,964 sq mi).

[citation needed] Its administrative center is the rural locality (a selo) of Ust-Bolsheretsk.

[7] The population of Ust-Bolsheretsk accounts for 25.4% of the district's total population.