Mariinsk is a town located in the Kemerovo Oblast of Russia. It is situated approximately 180 kilometers (110 miles) northeast of Kemerovo, which serves as the administrative center of the oblast.
The town is notable for being the location where the Trans-Siberian Railway crosses the Kiya River. According to census data, its population was recorded at 40,526 in 2010, following a steady trend from previous decades.