Firuzkuh County () is in Tehran province, Iran. Its capital is the city of Firuzkuh.
At the time of the 2006 National Census, the county's population was 37,416 in 10,414 households. The following census in 2011 counted 38,712 people in 11,828 households. The 2016 census measured the population of the county as 33,558 in 11,700 households.
Firuzkuh County's population history and administrative structure over three consecutive censuses are shown in the following table.
According to the information of the State Meteorological Organization of Iran, the long-term average annual rainfall ofÃÂ Firuzkuh is around 342.9 mm.