Zadonsk is a town and the administrative center of the Zadonsky District in Lipetsk Oblast, Russia. It is situated on the left bank of the Don River, which serves as the namesake for the settlement. The town is located approximately 92 kilometers (57 miles) southwest of Lipetsk, the administrative center of the oblast.
According to census data, the population of Zadonsk has fluctuated over recent decades. It recorded a population of 11,186 during the 1989 Soviet census, decreasing to 10,473 in 2002 and 9,698 in 2010, before reaching 9,887 as of the 2021 census.