Kuh Zin () is a village in Sain Qaleh Rural District of the Central District in Abhar County, Zanjan province, Iran.
At the time of the 2006 National Census, the village's population was 402 in 99 households. The following census in 2011 counted 384 people in 117 households. The 2016 census measured the population of the village as 453 people in 138 households.