Troitsk is a Russian town (from 1743), the administrative center of the Troitsk District of the Chelyabinsk Region.

The town stands at the confluence of rivers Uy (inflow of Tobol) and Uvelka, at the distance of 121 km to the south of Chelyabinsk.

Troitsk was founded in June, 1743 by Ivan Ivanovich Neplyuev, the governor of the Orenburg Territory, as a fortress of the Uy strengthened ambit, on the left bank of River Uy. The fortress was on the main caravan track, which passed from Asia to Europe.

In May, 1774 the fortress became the arena of Pugachyov’s revolt and was taken by storm by Yemelyan Pugachyov. Pugachyov did not remain in the fortress, but settled down at the distance of 1.5 km on a mount, which is now named after him. Pugachev held out there for one day only, since on the next day he was broken by colonel De-Kolong and forced to escape to Chelyabinsk.