Sain (Persian: صايين)[a] is a village in Ijrud-e Pain Rural District of Halab District in Ijrud County, Zanjan province, Iran.

At the time of the 2006 National Census, the village's population was 247 in 83 households.

[4] The following census in 2011 counted 279 people in 103 households.

[5] The 2016 census measured the population of the village as 471 people in 150 households.

This Ijrud County location article is a stub.