There are two main rules governing the distribution of high-temperature geothermal areas:
(1) their location along the boundaries between tectonic plates, and
(2) their alignment with the boundaries of mantle convection rolls.

In practice, almost all high-temperature areas are located either directly on, or immediately adjacent to, these lines. The main exceptions are Eyjafjallajökull, which is known to be connected to its neighbouring system beneath Mýrdalsjökull, and Hofsjökull, where the presence of a high-temperature area is somewhat uncertain.
The Torfajökull area lies somewhat distant from the plate boundary, yet it is the largest and most powerful of all high-temperature systems in Iceland. However, the area is highly fractured, suggesting that its roots may extend toward the plate boundary at depth.
Taken together, all 24 areas appear to occur within a similar structural context. Not every area is pointed out with an arrow, but in this way the consistency becomes more obvious.
List of Main High-Temperature Geothermal Areas in Iceland:
- Hveravellir
- Reykjadalur
- Prestahnúkur
- Geysir
- Hengill
- Reykjanes
- Kerlingarfjöll
- Mýrdalsjökull
- Hágöngur
- Vonarskarð
- Þeistareykir
- Öxarfjörður
- Gjástykki
- Krafla
- Námafjall
- Fremrinámar
- Hrúthálsar
- Askja
- Kverkfjöll
- Grímsvötn
- Jökulskálar
- Hofsjökull
- Eyjafjallajökull
- Torfajökull
