Hiking in Iceland
From well-worn Settlement-era trails to the more recently designated, Iceland is crisscrossed with thousands of walking paths. Quite a few of them, for example the Sprengisandur and Kjöl trails which run north-south across the island, have been traversed since the 9th century, and are mentioned in the Sagas of old. Though totally impassable during the long winter months, they were crucial in allowing people of the Viking era who lived in the remote north and east to get to the annual Althing parliament in Thingvellir. Today those two routes are graveled over for auto traffic, but there are a number of hiking trails that branch out from them into the desert highlands.
Another trail that's extremely popular these days is Laugavegur ("Pool Way," the same name as the main shopping street in Reykjavík). It runs from the beautiful Thorsmörk valley in the south of Iceland over a rugged highlands heath to Landmannalaugar multi-colored mountains and hot springs nature preserve. Most make it a 3 to 4 night hike, stopping at trail huts along the way (Iceland is dotted with these huts, which are all clearly marked on maps and in better guidebooks) though cross-country runners have taken it in half that time. A shorter trail in Thorsmörk is Fimmvörðuháls, 24-30 km hike between Eyjafjallajökull and Mýrdalsjökull ice caps. Most trailers finish the leg in one day.
For day trips, there are literally thousands of options to choose from. Just a twenty minute drive or bus ride from the center of Reykjavik takes you to Heiðmörk nature preserve with its gorgeous hills and forests, and a bit farther down Highway 1 takes you to the Hengill area, where eight different trails lead into the intensely geothermally active mountains and hot rivers east of the city. A more dramatic hike that's still super close to the capital and accessible by bus is the climb to the top of Esja, the mountain that guards over Reykjavik on the north side of the bay. Even just a few hours' driving north or east brings you to hundreds more walking and hiking paths through lava fields, up dormant volcanoes, along seabird-lined cliffs, to hidden waterfalls and through dense forests of birch and pine.
Most of the trails that are shown in guidebooks and pamphlets are clearly identifiable and very often marked with distance and time information at the trailhead. It's highly recommended that hikers stay on them at all times: it can't be stated often enough that Icelandic weather is fickle and dramatic, and the land unstable in many places (for example, a moss-covered lava field may look like an easy ramble, but hidden beneath the green are deep, sharp crevasses that you can easily fall into.) It's crucial as well to let your hiking intentions be known, even if it's the nearest gas station or shop, as every year hikers lose their way or get trapped in fog or storm.