For sure, Haukadalur is the most famous geyser and hot spring area in Iceland. It is home of Geysir, the namesake of all geysers, and of Strokkur, which is probably after Old Faithful in Yellowstone the most often photographed geyser all over the world. Geysir is also the name of the related volcanic system.
Located at the slope of the Laugarfjall volcano, the area comprises besides Geysir and Strokkur one additional active geyser of size, several small geysers, and a considerable number of other hydrothermal features. Boulders with engraved names identify the major attractions such as Geysir, Strokkur, Blesi, Konungshver, Litli Geysir, Litli Strokkur, Smiður and Sóði. Additionally, a sign with a map is available directly at the entrance of the site, guiding visitors to find the other officially named features. The geyser Óþerrishola and some other springs, also named ones, however, are more or less hidden or distant from the trail, so most visitors don't take notice of them.
Features in the northern part of the area around the spring Blesi are summarized here as Central Group. The southern part of the area is called Þykkvuhverir (sticky springs), features in this part are listed as belonging to the Þykkvuhverir Group. Some geysers and springs of both groups shall be presented here exemplarily.