Troitsk (Russian: Тро́ицк) is a town in Chelyabinsk Oblast, Russia, located 175 kilometers (109 mi) east of the southern Ural Mountains and approximately 110 kilometers (68 mi) south of Chelyabinsk on the border with Kazakhstan. It stands on the east-flowing Uy River, a branch of the Tobol River. Population: 78,372 (2010 Census); 83,862 (2002 Census); 90,077 (1989 Census).