Esfarayen (Persian: اسفراین, also Romanized as Esfarāyen; formerly, Meyanābād, Mīānābād, and Mīyānābād) is a city in and the capital of 
Esfarayen County, 
North Khorasan Province in 
Iran.
 At the 2006 census its population was 51,321, in 13,376 families. 
Esfarayen is one of the focal points
 ...see more  for residence of Aryan tribes after entering into Iran.
Reference: www.wikipedia.org