Ust-Ayaz (; , Ust-ÃÂyÃ¤à º) is a rural locality (a village) in Duvansky District, Bashkortostan, Russia. The population was 227 as of 2010. There are 5 streets.
Ust-Ayaz is located 104 km northwest of Mesyagutovo (the district's administrative centre) by road. Zaimka is the nearest rural locality.