Troitsk () is a rural locality (a selo), and one of two settlements in Petropavlovsky National Rural Okrug of Ust-Maysky District in the Sakha Republic, Russia, in addition to Petropavlovsk, the administrative center of the Rural Okrug. It is located from Ust-Maya, the administrative center of the district and from Petropavlovsk. Its population as of the 2002 Census was 74.