The
Highlands of Iceland cover most of the interior of
Iceland. They are situated above 400–500 metres and are mostly an uninhabitable
volcanic desert, because the water precipitating as rain or snow infiltrates so quickly into the ground that it is unavailable for plant growth. This results largely in a surface of grey, black or brown earth,
lava and
volcanic ashes. A few
oasis-like areas, such as
Herðubreiðarlindir near
Askja, are found only in proximity to rivers.