Atu (Persian: اتو)[a] is a village in, and the capital of, Kaseliyan Rural District of Zirab District, Savadkuh County, Mazandaran province, Iran.

[4] At the time of the 2006 National Census, the village's population was 565 in 133 households, when it was in the Central District.

[5] The following census in 2011 counted 351 people in 129 households.

[6] The 2016 census measured the population of the village as 510 people in 185 households,[2] by which time the rural district had been separated from the district in the establishment of Zirab District.

This Savadkuh County location article is a stub.