The BICOM research team has produced a briefing identifying the location of the Iranian military bases in Syria, detailing the role of the various Shia militias in the Syrian War and explaining the role of the Iranian Revolutionary Guards Corps (IRGC) in the conflict.
Suspected Iranian Base at Jabal ash Sharqi, approximately 13km from Damascus, Syria. Image used with permission of ImageSat International, copyright 2018.
Since the beginning of the Syrian civil war, Iran has sent thousands of troops and Shiite volunteers to support President Bashar al-Assad. The Iranian Revolutionary Guards Corps, Syrian National Defence Forces, Hezbollah, and several other Shiite militias have played a major role in the regime consolidating control and regaining territory, especially in the Battle for Aleppo in 2016. Iran has also reportedly established between 10-13 military bases across Syria.
The full briefing is available as a PDF below.