The following sights form a clockwise route around the lake, starting in Reykjahlíð. The distance around the lake is 36km (22 miles) by car.
In 1729, at the height of the Krafla eruption, a lava stream gobbled up two farmhouses and was headed straight for Reykjahlíð Church. At the last moment, the stream split and flowed into the lake. The church site is slightly elevated, but prayer was credited for averting disaster. The current church dates from 1962, and the vivid pulpit carving depicts the old church with the eruption in the background and "27 August, 1729" written in psychedelic font. All that remains of the old church is a foundation wall in the graveyard, and menacing heaves of lava are still clearly visible just beyond the graveyard wall.
The road to the church (and campsite and airfield) leads uphill from Hótel Reynihlíð. Near the end of the road, a pleasant trail leads west over the Eldhraun lava field, before crossing Route 87 and heading back to town along the north shore of the lake; allow 2 1/2 to 3 hours round trip.
Storagjá, Grjótagjá, Hverfell, and Dimmuborgir are connected by a recommended and well-marked trail, 7km (4.3 miles) or 2 1/2 to 3 hours in each direction. The trail begins from the Ring Road near Reykjahlíð, a few meters east of the Route 87 junction. Between Grjótagjá and Hverfell, the trail has two marked junctures -- one coinciding with the Hverfell parking area -- where you can detour to Mývatn Nature Baths.
The Storagjá fissure is not directly on the trail, but it's only a short detour, right from the trailhead. Partway along Storagjá is a staircase into the narrow fissure, descending about 5m (16 ft.) to a grassy floor. From there, assisted by a chain and rope, you can peer through a crack at a limpid, turquoise geothermal pool. The pool has recently cooled, attracting too much bacteria for safe swimming.
The steamy Grjótagjá fissure is set amid a geothermal valley of red and black gravel. Grjótagjá is 2km (1 1/4 miles) from the Storagjá-Dimmuborgir trailhead, and also reachable by car on Route 860, which connects with the Ring Road at two points. (Approaching from the west requires opening a sheep gate.) Near the parking area, two portals in the heaving lava lead to an enticing hot spring and pool. You can climb down and sit by the water, but it's too hot for swimming and fogs up camera lenses.
Hverfell -- the monolithic, striated black mountain shaped like a dog-bowl -- is unmistakable from anywhere in the vicinity. Hverfell -- which is often incorrectly identified as "Hverfjall" -- is a rare (and particularly enormous) example of a tephra explosion crater. It was formed 2,500 to 2,900 years ago, when rising magma met with groundwater, forcing a massive explosion of steam, ash, and rock. The rim is 1km (1/2 mile) in diameter, and the crater is 140m (459 ft.) deep, with a round nub at the center.
Hverfell's solemn, elemental grandeur cannot be fully appreciated without walking up to the crater rim. It's a 3km (1.9-mile) walk south from Grjótagjá, but you can also drive from the Ring Road to a parking area on Hverfell's north side. From there it's a 25-minute ascent. The trail loops completely around the rim, and the descent of the southern slope toward Dimmuborgir is steep and more challenging.
Meaning "Dark Castles," Dimmuborgir is a surreal lava field 1km (1/2 mile) in diameter. Its most distinctive features are the contorted crags and pillars reaching 20m (66 ft.) in height; nothing quite like them exists elsewhere, except on the ocean floor. Dimmuborgir was formed around 2,200 years ago, when molten lava formed a temporary "lava lake" on the site. Eventually the lava found an outlet and drained into Mývatn, but hardened pillars had formed around steam vents (lava finds steam chilling) and were left behind. The surface of the lava lake had half-congealed, and left all kinds of crusty "watermarks" on its way out.
Dimmuborgir is a 2km (1-mile) walk from the southern face of Hverfell, and can also be reached by car off the Ring Road. Plan on walking for an hour or two among the well-marked loop trails. The recommended Kirkjuvegur trail leads to Kirkjan (Church), a lava chute forming an archway. The more hazardous Krókastígur trail cuts through the middle of the site, past some of the most bizarre formations. Take care not to step into a fissure, and keep a close eye on children.
Höfði, a lakeside park on a small promontory, makes for a nice hour-long stroll along its peaceful forested pathways. The fragrant spruce and other trees were planted by Höfði's former owner. After entering the park, the trail branching off to the right leads to another juncture where you can detour uphill to a fantastic viewpoint. If instead you bear left after the park entrance and circle the promontory clockwise, you'll pass a clearing that overlooks Kalfarströnd. (The walk at Kalfarströnd farm, below, gives you a far better view.) Near Höfði's center is a rectangular lawn with benches -- a good picnic spot, if the midges aren't too bothersome.
The name Kalfarströnd refers to a farm on a grassy peninsula extending into Mývatn, and also to a series of lava columns (klasar) rising like strange mushrooms in a cove between the peninsula and Höfði Park. The turnoff from the Ring Road is 1km (1/2 mile) south of Höfði. After parking, pass through the farm gate, and the 30-minute, staked loop trail past the klasar is shortly ahead on the right. Kalfarströnd is sublime on a calm, soft-lit evening, with the klasar looming, the sky reflected in the aquamarine shallows, Höfði's evergreens in the background, and Mývatn's trim green islands etched in the distance. Bring your head net.
If Mývatn had a visual trademark, it would be Skútustaðagígar, the cluster of pseudocraters surrounding Stakhólstjörn pond, at the southwest shore of the lake. Pseudocraters, found primarily in Iceland and on Mars, are so named because they were never conduits for emerging lava. They're formed when lava flowing above ground heats subsurface water, causing explosions from steam and gas buildup. The Skútustaðagígar pseudocraters, each around 20m (66 ft.) deep, are quite striking from the road (or from Vindbelgjarfjall, below); but when viewed from the rims, they're simply grassy bowls. The walk around Stakhólstjörn takes an hour, or a 30-minute circuit begins opposite the Skútustaðir gas station or from Hótel Gígur.
The best all-around vista of Mývatn is from the top of Vindbelgjarfjall mountain, near the northwest shore. The 2-hour round-trip hike to the summit leaves from Vagnbrekka farm, off Route 848, 4km (2 1/2 miles) from the junction with the Ring Road. From the farm to the base of the mountain, the trail traverses a protected nesting area for waterfowl. The protected area is off limits from May 15 to July 20, but does not extend to the trail. The ascent is all scree and a bit slippery, but manageable.
Bjarnarflag & The Krafla Caldera
The Krafla caldera is the broad crater formed following eruptions of the volcano of the same name. The caldera ring is difficult to discern from the ground because its shape is broken and irregular, and its overall diameter is as large as that of Mývatn. "Krafla" can refer to the volcano cone, the geothermal area within the caldera, or the power plant exploiting that geothermal area. Leirhnjúkur and Stóra-Víti fall within the caldera, while Mývatn Nature Baths, Hverir, and Námafjall Ridge are parts of Bjarnarflag, the geothermal area south of the caldera.
Hverir, a large geothermal field, full of bubbling mud cauldrons and hissing steam vents, is 7km (4 1/4 miles) east of Reykjahlíð and easy to spot from the Ring Road. Walking through Hverir feels unreal, as minerals and chemicals in the earth form an exotic color spectrum unlike anything normally associated with nature. Some patches of ground are hot enough to cause severe burns, so stick to the paths. From Hverir, an hour-long trail ascends Námafjall, then cuts north to a parking area off the Ring Road at Námaskarð Pass, and then loops back to Hverir. Views are fabulous; but, again, be cautious, stay on the trail, and look out for scalding-hot patches of light-colored earth. The walk can be seriously gloppy after a rain.
Just east of Hverir, Route 863 branches off the Ring Road and leads north into the Krafla caldera. After about 8km (5 miles), the road passes under a pipeline arch at Krafla Geothermal Power Station (Kröflustöð), built in the 1970s. The visitor center (tel. 515-9000; www.landsvirkjun.is; Mon-Fri 12:30-3:30pm; Sat-Sun 1-5pm) has an informative free exhibit for those interested in the process of converting geothermal heat to electricity.
Gritty as burnt toast, Leirhnjúkur lava field is the best place to witness remnants of the 1975 to 1984 eruptions, and may be the most surreal landscape you will ever see. The parking area is clearly marked from Route 863, and from there it's a 15-minute walk to a geothermal field at the edge. Some visitors make the drastic mistake of looking at the boiling grey mud pots and color-streaked earth, and then heading back to their cars. Allow at least another hour for circling the trails, peering at the subtle range of color, texture, and moss inside each steamy rift. A good way to start is by proceeding from the geothermal field toward a bowl-shaped pseudocrater visible to the north. A recommended trail known as the Krafla Route leads straight from here to Reykjahlíð, and takes 3 to 4 hours one-way. Remember: Stick to the paths, watch your step, and beware of light-colored earth.
Route 863 dead-ends at a parking area by the rim of Stóra-Víti, a steep-sided explosion crater, formed in 1724, with a blue-green lake at the bottom. A trail circles the rim and descends on the far side to an interesting hot spring area. The route, which is worthwhile but not essential, takes about an hour round-trip and is not advised during muddy conditions.
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