In 2019, the village of Jafarabad was elevated to the status of a city. Chavar District was separated from the county in the establishment of Chavar County.
At the time of the 2006 census, the county's population was 193,222 in 42,207 households. The following census in 2011 counted 213,579 people in 52,391 households. The 2016 census measured the population of the county as 235,144 in 64,671 households.
Administrative divisions
Ilam County's population history and administrative structure over three consecutive censuses are shown in the following table.
↑Rahimi, Mohammad Reza (c. 2013) [Approved 14 December 2013]. Approval letter regarding the national divisions of Ilam province. rc.majlis.ir (Report) (in Persian). Ministry of the Interior, Political and Defense Commission. Proposals 89421/42/1/1 and 135295/42/4/1; Letter 158802/T38854H. Archived from the original on 23 August 2013. Retrieved 7 June 2023– via Islamic Parliament Research Center of the Islamic Republic of Iran.
123Jahangiri, Ishaq (c. 2022) [Approved 8 November 2019]. Letter of approval regarding national divisions in Ilam County, Ilam province. qavanin.ir (Report) (in Persian). Ministry of the Interior, Council of Ministers. Proposal 216963. Archived from the original on 17 November 2022. Retrieved 4 June 2023– via Laws and Regulations Portal of the Islamic Republic of Iran.
123Mokhbar, Mohammad (5 April 2023) [Approved 24 December 1401]. Letter of approval regarding the national divisions of Ilam province(PDF). rrk.ir (Report) (in Persian). Ministry of the Interior, Board of Ministers. Proposal 208825; Notification 242454/T58629H. Archived from the original(PDF) on 21 April 2023. Retrieved 12 November 2023.