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.
According to the 2016 census, Mashhad County had a population of 3,372,660 people, with 1,021,068 households. It is the most populated county within the province and the second most populous in the entire country, trailing only behind Tehran County.