Baatsagaan (, Baa white) is a sum (district) of Bayankhongor Province in southern Mongolia. Its area is 7,447 km<sup>2</sup>, and its population was 3,568 people in 2006.
The center of Baatsagaan is Bayansair village, located 125 km from the administrative center of the province (aimak), the city of Bayankhongor and 625 km from the national capital Ulaanbaatar. The climate is sharply continental.
The Böön Tsagaan Lake seated at the center of the district.
The district is divided into seven bags, which are:
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