Lahijan County (Persian: شهرستان لاهیجان) is in Gilan province, in northwestern Iran.

[3] At the time of the 2006 National Census, the county's population was 161,491 in 48,075 households.

[5] The 2016 census measured the population of the county as 167,544 in 58,378 households.

[2] Lahijan County's population history and administrative structure over three consecutive censuses are shown in the following table.

Media related to Lahijan County at Wikimedia Commons