sentences:  At the 2011 census, the population was 3,069,941.At the 2006 census, its population (including parts of the county later split from it to form Torqabeh e Shandiz County) was 2,848,637, in 746,652 families; excluding those portions, the population was 2,798,298 in 732,996 families.Mashhad County is the most populous county in Razavi Khorasan Province and the second most populus in the country behind Tehran County.