Onguday is a rural locality situated in the Altai Republic of Russia. It serves as the administrative center of the Ongudaysky District and is located along the Ursul River. The settlement is positioned approximately 210 kilometers (130 mi) from Gorno-Altaysk, which is the capital of the republic.
According to the 2010 Census, the population of Onguday was 5,655 residents. The community is primarily composed of ethnic Russians and Altai people.