[1] The administrative centre is Keflavík, which had 7,000 residents when it merged with the nearby town of Njarðvík and Hafnir in 1995 to create Reykjanesbær, which is the largest settlement outside the Greater Reykjavík area; in 2018, the region had a population of 17,805.

The peninsula is marked by active volcanism under its surface and large lava fields, allowing little vegetation.

There are numerous hot springs in the southern half of the peninsula, around the Kleifarvatn lake and the Krýsuvík geothermal area.

Using the hot and mineralized water coming down from the power station; the spa is known as the "Blue Lagoon" (Bláa Lónið).

[8] A great deal of volcanic unrest was occurring in this part of the Reykjanes Peninsula from 2020 onward, after nearly 800 years of inactivity.