At the 2016 census, Mashhad County's population was 3,372,660, in 1,021,068 households. It is the most populous county in the province and the second most populous in the country, behind Tehran County.
Mashhad County was the most populous county in the province and the second most populous in the nation, based on the 2016 census data. It had a population of 3,372,660 people and was distributed across 1,021,068 households.