Ust-Kalmansky District () is an administrative and municipal district (raion), one of the fifty-nine in Altai Krai, Russia. It is located in the center of the krai. The area of the district is . Its administrative center is the rural locality (a selo) of Ust-Kalmanka. Population: The population of Ust-Kalmanka accounts for 41.5% of the district's total population.