Tjarnargígur Crater is a striking volcanic crater in the Lakagígar (Laki) area of Iceland’s highlands, known for the small blue-green lake sitting inside it. It’s part of the landscape formed during the massive 1783–1784 Laki eruption, and the scenery out here is probably the most otherworldly spot in all of Iceland!
Access is via F206 and F207, which are highland F-roads, so a high-clearance 4×4 is required, and these roads are only open in summer. Along the way, there are unbridged river crossings, which can become deeper or more difficult after rain, so it’s important to check current road conditions before heading out. (use https://umferdin.is/en)
There’s a small parking area near the crater (to find parking put "Tjarnargígur Crater Parking with Toilet" into Google Maps, and as the name suggests, yes, there is a restroom here), and from there it’s just a short, easy walk to the rim where you can look down into the crater and see the lake.
The trail is well-marked, but the hike route is linked below :)